LIBRARY 

OF 

A.  KOFOID. 


b&c-L    U.b. 


THE  LIBRARY 

OF 
THE  UNIVERSITY 

OF  CALIFORNIA 


PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


ERKELEY 

I2R-\RY 

NIVERSITY   OF 
CALIFORNIA 


EARTH 

CIENCES 

JBRARY 


MANUAL 


OP 


MINEIjALOGY  JIND  LITHOLOGT, 


CONTAINING 


Tne  Elements  of  tie  Science  of  Minerals  and  Rods. 


FOR  THE  USE  OF 


THE  PRACTICAL  MINERALOGIST  AND  GEOLOGIST,  AND  FOR  INSTRUCTION 
IN  SCHOOLS  AND  COLLEGES. 


BY  JAMES   D.    DANA. 


THIRD    EDITION. 

RE-ARRANUKD    AND    RE-WHITTEN. 

FOURTEENTH    THOUSAND. 
ILLUSTRATED  BY  NUMEROUS   WOOD-CUTS. 


NEW  YORK  : 
JOHN    WILEY    &   SONS. 

1886. 


COPYRIGHT, 

1878, 
BY  JOHN  WILEY  &  SONS. 


EARTH 

SCIENCES 
LIBRARY 

PEE  FACE. 


THIS  Manual  in  its  present  shape  is  new  throughout.  In  the  reno- 
vation it  has  undergone, new  illustrations  have  been  introduced,  an'im- 
proved  arrangement  of  the  species  has  been  adopted,  the  table  for  the 
determination  of  minerals  has  been  reconstructed,  and  the  chapter  on 
rocks  has  been  expanded  to  a  length  and  fullness  that  renders  it  a 
prominent  part  of  the  work.  But  while  modified  greatly  in  all  its 
parts,  it  is  still  simple  in  its  methods  of  presenting  the  facts  in  crys- 
tallography, and  in  all  other  explanations  ;  and  special  prominence  is 
given,  as  in  former  editions,  to  the  more  common  minerals,  with  only 
a  brief  mention  of  others.  The  old  practical  feature  is  retained  of 
placing  the  ores  under  the  prominent  metal  they  contain,  and  of  giving 
in  connection  some  information  as  to  mines  and  mining  industry. 

The  student  is  referred  to  the  Text-book  of  Mineralogy,  prepared 
mainly  by  Mr.  E.  S.  DANA,  for  a  detailed  exposition  of  the  subject  of 
crystallography  after  Naumann's  and  Miller's  systems,  and  also  of 
optical  mineralogy  and  other  piiysical  branches  of  the  science;  to 
the  Manual  of  Determinative  Mineralogy  and  Blowpipe  Analysis  by 
Professor  GEORGE  J.  BRUSH,  for  a  thorough  work  on  the  use  of  the 
blowpipe,  and  complete  tables  for  the  determination  of  minerals; 
and  to  the  author's  Descriptive  Mineralogy  and  its  Appendixes  for  a 
comprehensive  treatise  on  all  known  minerals. 

JAMES  D.  DANA. 
NEW  HAVEN,  Nov.  1,  1878.. 


1923: 


TABLE    OF    CONTEXTS. 

MINERALOGY. 

MINERALS  :  General  Remarks I 

I.    CRYSTALLIZATION   OF  MINERALS:    CRYSTALLOGRAPHY. 

1.  General  Remarks  on  Crystallization 4 

2.  Descriptions  of  Crystals 8 

Explanation  of  Terms 8 

Measurement  of  Angles  ;  Goniometers 9 

I.  SYSTEMS  o;  \LLIZATIOX:    Forms  and    Struc- 

ture of  Crystals 14 

1.  Isometric  System 1? 

2.  Dimetric  or  Tetragonal  System  30 

3.  Trimetric  or  Orthorhombic  System 37 

4.  Monoclinic  System  40 

5.  Triclinic  System 43 

6.  Hexagonal  System 45 

1.  Hexagonal  Section 46 

2.  Rhombohedral  Section 49 

7.  Distinguishing  Characters  of  the  Systems 54 

II.  TWIN  OR  COMPOUND  CRYSTALS 55 

III.  CRYSTALLINE  AGGREGATES 58 

II.    PHYSICAL  PROPERTIES  OF  MINERALS. 

1.  Hardness 63 

2.  Tenacity 64 

3.  Specific  Gravity 64 

4.  Refraction  and  Polarization 66 

5.  Diaphaneity,  Lustre,  Color TO 

6.  Electricity  and  Magnetism 73 

7.  Taste,  Odor 74 

V 


yj  TABLE  OF  CONTENTS. 

III.  CHEMICAL  PROPERTIES  OF  MINERALS. 

PAGE 

1.  Chemical  Composition 76 

2.  Chemical  Reactions 81 

1.  Trials  in  the  Wet  Way 81 

2.  Trials  with  the  Blowpipe 83 

IV.  DESCRIPTIONS  OF  MINERALS. 

•      1.  Classification 91 

2.  General  Remarks  on  Ores 92 

I.  MINERALS  CONSISTING  OF  THE  ACIDIC  ELEMENTS. 

1.  Sulphur  Group 94 

2.  Boron  Group 97 

8.  Arsenic  Group 98 

4.  Carbon  Group 102 

II.  MINERALS  CONSISTING  OF  THE  BASIC  ELEMENTS  WITH 

OR   WITHOUT   ACIDIC — THE    SILICATES    EXCLUDED. 

Gold 109 

Silver  and  its  Compounds 116 

Platinum,  Iridium,  Ruthenium 124 

Palladium 127 

Mercury  and  its  Compounds 128 

Copper  and  its  Compounds 130 

Lead  and  its  Compounds. ., 145 

Zinc  and  its  Compounds 154 

Cadmium,  Tin 159 

Compounds  of  Titanium 162 

Cobalt  and  Nickel  and  their  Compounds 163 

Uranium  and  its  Compounds 169 

Iron  and  its  Compounds 171 

Manganese  and  its  Compounds 188 

Compounds  of  Aluminum 192 

Compounds  of    Cerium,  Yttrium,  Erbium,  Lanthanum  and 

Didymium 201 

Compounds  of  Magnesium 204 

Compounds  of  Calcium 207 

Compounds  of  Barium  and  Strontium 220 

Compounds  of  Potassium  and  Sodium 223 

Compounds  of  Ammonium 230 

Compounds  of  Hydrogen , 231 


TABLE    OF    CONTENTS.  yij 

III.  SILICA  AND  SILICATES. 

1.     SILICA.  TAGE 

Quartz 233 

Opal ; 239 

2.  SILICATES. 
General  Remarks 242 

1.  Anhydrous  Silicates. 

1.  Bisilicates 243 

Pyroxene  and  Amphibole  Group. 244 

Beryl,  etc ! 252 

2.  Unisilicates 254 

Chrysolite  Group 255 

Garnet  Group 256 

Zircon  Group 259 

Idocrase,  Epidote,  etc 261 

Axinite,  lolite , ...  264 

Mica  Group 265 

Scapolite  Group 268 

Nephelite,  Sodalite,  Leucite 269 

Feldspar  Group 272 

3.  Subsilicates 280 

Chondrodite,  Tourmaline -. 281 

Andalusite,  Fibrolite,  Cyanite 284 

Topaz,  Euclase 288 

Datolite,  Sphene,  Staurolite , . .  289 

2.   Hydrous   Silicates. 

1.  General  Section 292 

Pectolite,  Laumontite,  Apophyllite 293 

Prelinite,  Allophane 295 

2.  Zeolite  Section , 297 

Thomsonite,  "Natrolite,  Analcite,  Cliabazite 298 

Harmotome,  Stilbite,  Heulandite 301 

3.  Margarophyllite  Section 804 

Talc,  Pyrophyllite,  Sepiolite SOI 

Serpentine,  Deweylitc,  Saponite 307 

Kaolinite,  Finite 310 

Hydromica  Group 312 

Fanlunite,  Hisingerite 315 

Chlorite  Group 316 


yiH  TABLE    OF    CONTENTS. 

IV.  HYDROCARBON  COMPOUNDS. 

PACK 

1.  Simple  Hydrocarbons 321 

2.  Oxygenated  Hydrocarbons 325 

3.  Asphaltum  and  Mineral  Coals 328 

SUPPLEMENT  TO  DESCRIPTIONS  OF  SPECIES. 

1.  Catalogue  of  American  Localities  of  Minerals 333 

2.  Brief  Notice  of  Foreign  Mining  Regions 375 

IY.    DETERMINATION  OF  MINERALS. 

General  Remarks 379 

Table  for  the  Determination  of  Minerals. .  .  384 


ON    BOCKS. 

1.  Constituents  of  Rocks 409 

2.  Classes  of  Rocks 413 

3.  On  some  Characteristics  of  Rocks 414 

Use  of  the  Microscope  in  the  Study  of  Rocks 422 

4.  Kinds  of  Rocks 424 

1.  Fragmental  Rocks,  exclusive  of  Limestones 426 

2.  Limestones  or  Calcareous  Rocks 430 

3.  Crystalline  Rocks,  exclusive  of  Limestones 434 

1.  Siliceous  Rocks 435 

2.  Mica  and  Potash-Feldspar  Series 437 

-8.  Mica  and  Soda-lime  Feldspar  Series 443 

4.  Hornblende  and  Potash-Feldspar  Series 444 

5.  Hornblende  and  Soda-lime  Feldspar  Series 446 

C.  Pyroxene  and  Soda-lime  Feldspar  Series 450 

7.  Pyroxene,  Garnet,  Epidote,  and  Chrysolite  Rocks, 

containing  little  or  no  Feldspar 452 

8.  Hydrous  Magnesian  and  Aluminous  Recks 453 

9.  Iron-ore  Rocks ...  .  455 


MINERALOGY. 


MINERALS, 

MINERALS  are  the  materials  of  which  the  earth  consists,  and 
plants  and  animals  the  living  beings  over  the  surface  of  the 
mineral-made  globe.  A  few  rocks,  like  limestone  and  quartz- 
yte,  consist  of  a  single  mineral  in  more  or  less  pure  state ;  but 
the  most  of  them  are  mixtures  of  two  or  more  minerals. 
Through  rocks  of  each  kind  various  other  minerals  are  often 
distributed,  either  in  a  scattered  way,  or  in  veins  and  cavities. 
Gems  are  the  minerals  of  jewelry;  and  ores,  those  that  are  im- 
portant for  the  metal  they  contain.  Water  is  a  mineral,  but 
generally  in  an  impure  state  from  the  presence  of  other  miner- 
als in  solution.  The  atmosphere,  and  all  gaseous  materials  set 
free  in  volcanic  and  other  regions,  are  mineral  in  nature, 
although,  because  of  their  invisibility,  seldom  to  be  found 
among  the  specimens  of  mineral  cabinets.  Even  fossils  are 
mineral  in  composition.  This  is  true  of  coal  which  has  come 
from  buried  plant-beds,  and  amber  from  the  buried  resin  of 
ancient  trees,  as  well  as  of  fossil  shells  and  corals. 

It  is  sometimes  said  that  minerals  belong  to  the  mineral 
kingdom,  as  plants  to  the  vegetable  kingdom,  and  animals  to 
the  animal  kingdom.  Substituting  the  term  inorganic  for  min- 
eral, the  statement  is  right ;  for,  as  there  are  the  two  kingdoms 
of  life,  so  there  is  in  Nature  what  may  be  called  a  kingdom,  or 
grand  division,  including  all  species  not  made  through  the 
organizing  principle  of  life.  But  this  inorganic  kingdom  is  not 
restricted  to  minerals ;  it  embraces  all  species  made  by  inor- 
ganic forces — those  of  the  earth's  crust  or  surface,  and,  also, 
whatever  may  form  under  the  manipulations  of  the  chemist. 
The  laws  of  composition  and  structure,  exemplified  in  the  consti- 
tution of  rocks,  are  those  also  of  the  laboratory.  A  species  mada 


2  CHAEACTEES    OI    MINEEALS. 

by  art,  as  we  term  it,  is  not  a  product  of  art,  but  a  result  solely 
of  the  fundamental  laws  of  composition  which  are  at  the  basis 
of  all  material  existence;  and  the  chemist  only  supplies  the 
favorable  conditions  for  the  action  of  those  laws.  Mineral 
species,  are  then,  but  a  very  small  part  of  those  which  make  up 
the  inorganic  kingdom  or  division  of  Nature. 


CHARACTERS  OF  MINERALS. 

1.  Minerals,  unlike   most  rocks,  have  a    definite    chemical 
composition.      This  composition,   as  determined  by   chemical 
analysis,  serves  to  define  and  distinguish  the  species,  and  indi- 
cates their  profoundest  relations.     Owing  to  difference  in  com- 
position, minerals  exhibit  great  differences  when  heated,  and 
when  subjected  to  various  chemical  reagents,  and  these  peculi- 
arities are  a  means  of  determining  the  kind  of  mineral  under 
examination  in  any  case.     The  department  of  the  science  treat- 
ing of  the  composition  of  minerals  and  their  chemical  reactions 
is  termed  CHEMICAL  MINERALOGY. 

2.  Each  mineral,  with  few  exceptions,  has  its  definite  form, 
by  which,  when  in  good  specimens,  it  may  be  known,  and  as 
truly  so  as  a  dog  or  cat.     These  forms  are  cubes,  prisms,  double 
pyramids,  and  the  like.     They  are  included  under  plane  sur- 
faces arranged  in  symmetrical  order,  according  to  mathematical 
law.     These  forms,  in  the  mineral  kingdom,  are  called  crystals. 
Besides  form  there  is  also,  as  in  living  individuals,  a  distinctive 
internal  structure  for  each  species.     The  facts  of  this  branch  of 
the  science  come  under  the  head  of  CRYSTALLOGRAPHIC  MINER- 
ALOGY. 

3.  Minerals  differ  in  hardness — from  the  diamond  at  one  end 
of  the  scale  to  soapstone  at  the  other.     There  is  a  still  lower 
limit  in  liquids  and  gases ;  but  of  the  hardness  or  cohesion  in  this 
part  of  the  series  the  mineralogist  has  little  occasion  to  take 
note. 

Minerals  differ  in  specific  gravity,  and  this  character,  like 
hardness,  is  a  most  important  means  of  distinguishing  species. 

Minerals  differ  in  color ',  transparency,  lustre,  and  other  opti- 
cal characters. 

A  few  minerals  have  taste  and  odor,  and  when  so  these  char- 
acters are  noticed  in  descriptions. 

The  facts  and  principles  relating  to  the  above  character! 
are  embraced  in  the  department  of  PHYSICAL  MINERALOQ  r. 

In  addition  to  the  above-mentioned  branches  of  the  science 


CHARACTERS    OF   MINERALS.  3 

of  minerals  there  is  also  (4)  that  of  DESCRIPTIVE  MINERALOGY, 
under  which  are  included  descriptions  of  the  mineral  species ; 
and  (5)  that  of  DETERMINATIVE  MINERALOGY,  which  gives  a 
systematic  review  of  the  methods  for  determining  or  distinguish- 
ing minerals. 

These  different  branches  of  ihe  subject  are  here  taken  up  in 
the  following  order  •  I.  Crystallographic  Mineralogy ;  £1.  Phys- 
ical Mineralogy;  III.  Chemical  Mineralogy;  IV.  Descriptive 
Mineralogy ;  V.  Determinative  Mineralogy.  On  account  of 
the  brief  manner  in  which  the  subjects  are  treated  in  this 
volume,  the  heads  used  for  the  several  parts  are,  (1)  The  Crys- 
tallization of  Minerals  •  (2)  Physical  Properties  of  Minerals  / 
(3)  CJiemical  Properties  of  ^Minerals  ;  (4)  Descriptions  o 
ties  /  (5)  Determination  of  Minerals. 


4 


CRYSTALLOGRAPHY. 


1.  CRYSTALLIZATION  OF  MINERALS: 
CRYSTALLOGRAPHY. 

1.  GENERAL  REMARKS  ON  CRYSTALLIZATION. 

THE  attraction  which  produces  crystals  is  one  of  the  funda- 
mental properties  of  matter.  It  is  identical  with  the  cohesion 
of  ordinary  solidification  ;  for  there  are  few  cases  outside  of  the 
kingdoms  of  life  in  which  solidification  takes  place  without  some 
degree  of  crystallization.  Cohesive  attraction  is,  in  fact,  the 
organizing  or  structure-making  principle  in  inorganic  nature,  it 
producing  specific  forms  for  each  species  of  matter,  as  life  does 
for  each  living  species.  A  bar  of  cast-iron  is  rough  and  hackly 
in  surface,  because  of  the  angular  crystalline  grains  which  the 
iron  assumed  as  solidification  took  place.  A  fragment  of  mar- 
ble glistens  in  the  sun,  owing  to  the  reflection  of  light  from  in- 
numerable crystalline  surfaces,  every  grain  in  the  mass  having 
its  crystalline  structure.  When  the  cold  of  winter  settles  over 
+he  earth  in  the  higher  temperate  and  colder  latitudes  it  is  the 


CRYSTALS  OP   SNOW. 


•ignal  for  crystallization  over  all  out-door  nature;  the  air  « 
filled  with  crystal  flakes  when  it  snows ;  the  streams  become 
coated  with  an  aggregation  of  crystals  called  ice;  and  windows 
are  covered  with  frost  because  crystal  has  been  added  to  crystal 


CEYSTALLOGEAPHY. 


5 


in  long  feathered  lines  over  the  glass — Jack  Frost's  work  being 
the  making  of  crystals.  Water  cannot  solidify  without  crystal- 
lizing,  and  neither  can  iron  nor  lead,  nor  any  mineral  material, 
with  perhaps  half  a  dozen  exceptions.  Crystallization  produces 
masses  made  of  crystalline  grains  when  it  cannot  make  distinct 
crystals.  Granite  mountains  are  mountains  of  crystals,  each 
particle  being  crystalline  in  nature  and  structure.  The  lava 
current,  as  it  cools,  becomes  a  mass  of  crystalline  grains.  In 
fact  the  earth  may  be  said  to  have  crystal  foundations ;  and  if 
there  is  not  the  beauty  of  external  form,  there  is  everywhere 
the  interior,  profounder  beauty  of  universal  law: — the  same  law 
of  symmetry  which,  when  external  circumstances  permit,  leads 
to  the  perfect  crystal  with  regular  facets  and  angles. 

Crystals  are  alone  in  making  known  the  fact  that  this  law 
of  symmetry  is  one  of  the  laws  of  cohesive  attraction,  and  that 
under  it  this  attraction  not  only  brings  the  particles  of  matter 
into  forms  of  mathematical  symmetry,  but  often  develops  scores 
of  brilliant  facets  over  their  surface  with  mathematical  exact- 
ness of  angle,  and  the  simplest  of  numerical  relations  in  their 
positions.  Crystals  teach  also  the  more  wonderful  fact  that 
the  same  species  of  matter  may  receive,  under  the  action  of  this 
attraction,  through  some  yet  incomprehensible  changes  in  its 
condition,  a  great  diversity  of  forms — from  the  solid  of  half  a 
dozen  planes  to  one  of  scores.  The  following  figures  represent  a 
few  of  the  forms  in  a  common  species,  pyrite,  a  compound  of 
iron  and  sulphur. 


CRYSTALLOGRAPHY. 
9. 


12. 


15. 


Many  more  figures  might  be  given  for  this  one  species,  py- 
lite.  The  various  forms  or  planes  in  any  such  case  have,  it  is 
true,  mutually  dependent  relations — a  fact  often  expressed  by 
Baying  that  they  have  a  common  fundamental  form.  But  it  is 
none  the  less  a  remarkable  fact,  giving  profound  interest  to  the 
Bubject,  that  the  attraction,  while  having  this  degree  of  unicy 
in  any  species,  still,  under  each,  admits  of  the  multitudinous 
variations  needed  to  produce  so  diverse  results. 

At  the  time  of  crystallization  the  material  is  usually  in  a 


CRYSTALLOGRAPHY.  7 

state  of  fusion,  or  of  gas  or  vapor,  or  of  solution.  In  the  case 
of  iron  the  crystallization  takes  place  from  a  state  of  fusion,  and 
while  the  result  is  ordinarily  only  a  mass  of  crystalline  grains^ 
distinct  crystals  are  sometimes  formed  in  any  cavities.  If  in 
the  cooling  of  a  crucible  of  melted  lead,  bismuth,  or  sulphur,  the 
crust  be  broken  soon  after  it  forms,  and  the  liquid  part  within  be 
turned  out,  crystals  will  be  found  covering  the  interior.  Here, 
also,  is  crystallization  from  a  state  of  fusion.  When  frost  or 
snow-flakes  form  it  exemplifies  crystallization  from  a  state  of 
vapor.  If  a  saturated  solution  of  alum,  made  with  hot  water, 
be  left  to  cool,  crystals  of  alum  after  awhile  will  appear,  and 
will  become  of  large  size  if  there  is  enough  of  the  solution.  A 
solution  of  common  salt,  or  of  sugar,  affords  crystals  in  the 
same  way.  Again,  whenever  a  mineral  is  produced  through 
the  change  or  decomposition  of  another,  and  at  the  same  time 
assumes  the  solid  state,  it  takes  at  once  a  crystalline  structure, 
if  it  does  not  also  develop  crystals. 

Further,  the  crystalline  texture  of  a  solid  mass  may  often  be 
changed  without  fusion :  e.  g.,  in  tempering  steel  the  bar  is 
changed  from  coarse-grained  steel  to  fine-grained  by  heating 
and  then  cooling  it  suddenly  in  cold  water,  and  vice  versa,  and 
this  is  a  change  in  every  grain  throughout  the  bar. 

Thus  the  various  processes  of  solidification  are  processes  of 
crystallization,  and  the  most  universal  of  all  facts  about  miner- 
als is  that  they  are  crystalline  in  texture.  A  few  exceptions 
have  been  alluded  to,  and  one  example  of  these  is  the  mineral 
opal,  in  which  even  the  microscope  detects  no  evidence  of  a 
crystalline  condition,  except  sometimes  in  minute  portions  sup- 
posed not  to  be  opal.  But  if  we  exclude  coals  and  resiris  this 
mineral  stands  almost  alone.  Such  facts,  therefore,  do  not 
affect  the  conclusion  that  a  knowledge  of  crystallography  is  of 
the  highest  importance  to  the  mineralogist.  It  is  important 
because — 

1.  A  study  of  the  crystalline  forms  and  structure  of  minerals 
is  a  convenient  means  of  distinguishing  species — the  crystals 
of  a   species  being   essentially  constant  in   structure   and  ia 
angles. 

2.  The  most  important  optical  characters  depend   on   the 
crystallization,  and  have  to  be  learned  from  crystals. 

3.  The  profoundest  chemical  relations  of  minerals  are  often 
exhibited  in  the  relations  of  their  crystalline  forms. 

4.  Crystallization  opens  to  us  nature  at  her  foundation  work 
*nd  illustrates  its  mathematical  character. 


CRYSTALLOGRAPHY. 


2.  DESCRIPTIONS  OP  CRYSTALS. 

In  describing  crystals  there  are  two  subjects  for  consider* 
tion :  First,  FORM  ;  and  secondly,  STRUCTURE. 

A.  FORM, — Under  form,  come  up  for  description,  not  only 
the  general  forms  of  crystals,  but  also — 

(1.)  The  systems  of  crystallization,  that  is,  the  relations  ol 
all  crystalline  forms,  and  their  classification. 

(2.)  The  mutual  relations  of  the  planes  of  a  crystal  as  ascer- 
tained through  their  positions  and  the  angles  between  them. 

(3.)  The  distortions  of  crystals.  The  perfection  of  symmetry 
exhibited  in  the  figures  of  crystals,  in  which  all  similar  planes 
are  represented  as  having  the  same  size  and  form,  is  seldom 
found  in  nature,  and  the  true  form  is  often  greatly  disguised  by 
this  means.  The  facts  on  this  point,  and  the  methods  of  avoid- 
ing wrong  conclusions  need  to  be  understood,  and  these  are 
given  beyond.  With  all  such  imperfections  the  angles  of  crys- 
tals remain  essentially  constant.  There  are  irregularities  also 
from  other  sources. 

(4.)  Twin  or  compound  crystals.  With  some  species  twins 
are  more  common  than  regular  crystals. 

(5.)  Crystalline  aggregates,  or  combinations  of  imperfect 
crystals,  or  of  crystalline  grains. 

Explanations  of  Terms. 

The  following  are  explanations  of  a  few  terms  used  in  connection 
with  this  subject : 

1.  OctaJiedron. — A  solid  bounded  by  eight  equal  triangles.     They  are 
equal  equilateral  triangles  in  the  regular  octahedron  (Fig.  2,  p.  17) ; 
equal  isosceles  triangles  in  the  square  octahedron  (Fig.  17,  p.  32) ;  equal 
inequilateral  triangles  in  the  rhombic  octahedron  (Fig.  8,  p.  37). 

2.  Double  six-sided  pyramids.    Double  eight-sided  pyramids.     Double 
twelve-sided  pyramids. — Solids  made  of  two  equal  equilateral  six-sided, 
or  eight-sided,  or  twelve-sided,  pyramids  placed  base  to  base  (Fig.  20, 
p.  32,  and  6,  10,  pp.  46,  47). 

3.  Right  prisms.     Oblique  prisms. — Eight  prisms  are  those  that  are 
erect,  all  their  sides  being  at  right  angles  to  the  base.    When  inclined, 
they  are  called  oblique  prisms. 

4.  Interfacial  angle. — Angle  of  inclination  between  two  faces  or  planes. 

5.  Similar  planes.     Similar  angles.  — The  lateral  faces  of  a  square 

Srism  (Fig.  2,  p.  14)  are  equal  and  have  like  relations  to  the  axes,  and 
ence  they  are  said  to  be  similar.     Solid  angles  are  similar  when  the 
plane  angles  are  equal  each  for  each,  and  the  enclosing  planes  are  sev- 
erally similar  in  their  relations  to  the  axes. 

6.  Truncated.    Bevelled. — An  edge  of  a  crystal  is  said  to  be  truncated 
when  it  is  replaced  by  a  plane  equally  inclined  to  the  enclosing  planes, 
as  in  Fig.  13,  p.  19 ;  and  it  is  bevelled  when  replaced  by  two  planea 


CRYSTALLOGRAPHY.  9 

equally  inclined  severally  to  the  adjoining  faces.  Only  edges  that  are 
formed  by  the  meeting-  of  two  similar  planes  can  be  truncated  or  bev- 
elled. The  angle  between  the  truncating  plane  and  the  plane  adjoining 
it  on  either  side  always  equals  90 '  plus  half  the  interfacial  angle  ovei 
the  truncated  edge.  When  a  rectangular  edge,  or  one  of  90°,  is  trun- 
cated, this  angle  is  accordingly  135°  (  =  90°-v45°) ;  when  an  edge  of  70°. 
it  is  125°  (=90° +  35°) ;  when  an  edge  of  140°,  it  is  160°  (=90°  4- 70°). 

7.  Zme. — A  zone  of  planes  includes  a  series  of  planes  having  the 
edges  between  them,  that  is,  their  mutual  intersections,  all  parallel. 
Thus  ir.  Fig.  14,  on  page  6,  0  at  top  of  figure,  J2,  %},  0  in  front,  and 
two  planes  below,  and  others  on  the  back  of  the  crystal  are  in  one  zone, 
a  vertical  zone.  Again,  in  the  same  figure,  0  at  top,  42,  3|,  22,  42,  i2,  42, 
22,  3:|,  and  the  continuation  of  this  series  below  and  over  the  back  of 
the  crystal  lie  in  another  vertical  zone.  And  so  in  other  cases,  in 
other  directions.  All  planes  in  the  same  zone  may  be  viewed  as  on  the 
circumference  of  the  same  circle.  The  planes  of  crystals  are  generally 
all  comprised  in  a  few  zones,  and  the  study  of  the  mathematics  of 
crystals  is  largely  the  study  of  zones  of  planes. 

Axes. — Imaginary  lines  in  crystals  intersecting  one  another  at  their 
centres.  Axes  are  assumed  in  order  to  describe  the  positions  of  the 
planes  of  crystals.  In  each  system  of  crystallization  there  is  one  verti- 
cal axis,  and  in  all  but  hexagonal  forms  there  are  two  lateral  axes. 

Diametral  sections. — The  sections  of  crystals  in  which  lie  any  two  of 
the  axes.  In  forms  having  two  lateral  axes,  there  are  two  vertical 
diametral  sections  and  one  basal. 

Diametral  prisms. — Prisms  whose  sides  are  parallel  to  the  diametral 
sections. 

Measurement  of  Angles. 

The  angles  of  crystals  are  measured  by  means  of  instruments  called 
goniometers.  These  instruments  are  of  two  kinds,  one  the  common 
goniometer,  the  other,  the  reflecting  goniometer. 

The  common  goniometer  depends  for  its  use  on  the  very  simple  prin- 
ciple that  when  two  straight  lines  cross  one  an- 
other, as  A  E,  C  D,  in  the  annexed  figure,  the  parts 
will  diverge  equally  on  opposite  sides  of  the  point 
of  intersection  (O)  ;  that  is  in  mathematical  lan- 
guage, the  angle  A  O  D  is  equal  to  the  angle  C  O  E, 
and  A  O  C  is  equal  to  D  0  E. 

A  common  form  of  the  instrument  is  represented  in  the  figure  on 
page  10. 

The  two  arms  a  b,  c  d,  move  on  a  pivot  at  0,  and  their  divergence, 
or  the  angle  they  make  with  one  another,  is  read  off  on  the  graduated 
arc  attached.  In  using  it,  press  up  between  the  edges  a  o  and  c  0, 
the  edge  of  the  crystal  whose  angle  is  to  be  measured,  and  con- 
tinue thus  opening  the  arms  until  these  edges  lie  evenly  against  the 
faces  that  include  the  required  angle.  To  insure  accuracy  in  this 
respect,  hold  the  instrument  and  crystal  between  the  eye  and  the  light, 
and  observe  that  no  Jight  passes  between  the  arm  and  the  applied  faces 
of  the  crystal.  The  arms  may  then  be  secured  in  position  by  tighten- 
ing the  screw  at  o  ;  the  angle  will  then  be  measured  by  the  distance  on 
the  arc  from  k  to  the  left  or  outer  edge  of  the  arm  c  d,  this  edge  being  in 
the  line  of  o.  the  centre  of  motion.  As  the  instrument  stands  in  tho 


10 


CRYSTALLOGRAPHY. 


figure,  ib  reads  45°.  The  arms  have  slits  at  g  h,  n  p,  by  which  the  part* 
a  o,  co,  may  be  shortened  so  as  to  make  them  more  convenient  for 
measuring  small  crystals. 

In  the  best  form  of  the  common  goniometer  the  arc  is  a  complete 


circle,  of  larger  diameter  than  in  the  above  figure,  and  the  arms  a?e 
separate  from  it.  After  making  the  measurement,  the  arms  are  laid 
upon  the  circle,  with  the  pivot  at  the  centre  of  motion  inserted  in  a 
socket  at  the  centre  of  the  circle.  The  inner  edge  of  one  of  the  arms 
is  then  brought  to  zero  on  the  circle,  and  the  angle  is  read  off  as  before. 

With  a  Ifttle  ingenuity  the  student  may  construct  a  goniometer  for 
himself  tbafc  will  answer  a  good  purpose.  A  semicircle  may  be  de- 
scribed on  mica  or  a  glazed  card,  and  graduated.  The  arms  might  also 
be  made  of  stiff  card  for  temporary  use  ;  but  mica,  bone,  or  metal  is 
better.  The  arms  should  have  the  edges  straight  and  accurately  paral- 
lel, and  be  pivoted  together.  The  instrument  may  be  used  like  that  last 
described,  and  will  give  approximate  results,  sufficiently  near  for  dis- 
tinguishing most  minerals.  The  ivory  rule  accompanying  boxes  of 
mathematical  instruments,  having  upon  it  a  scale  of  sines  for  measuring 
angles,  will  answer  an  excellent  purpose,  and  is  as  convenient  as  the  arc. 

In  making  such  measurements  it  is  important  to  have  in  mind  the 
fact  that— 

1.  The  sum  of  the  angles  about  a  centre  is  360°. 

2.  In  a  rhomb,  as  in  a  square,  the  sum  of  the  plane  angles  is  360°. 
In  any  polygon,  the  supplements  of  the  Angles  equals  360°,  whatever 

itte  number  of  sides.  For  example  :  in  a  square,  the  four  angles  are 
each  90°,  and  hence  the  supplements  are  90°,  and  4x90=360  ;  again, 
in  a  regular  hexagon  the  six  angles  are  each  120,  the  supplements  are 
60°,  and  6  x  60—360.  So  for  all  polygons,  whether  regular  or  irregular. 
In  measuring  the  angles  it  is  therefore  convenient  to  take  down  the 
supplements  of  the  angles.  This  principle  is  conveniently  applied  in 
the.  measurement  of  all  the  angles  of  a  zone  of  planes  around  the 
crystal ;  for  the  sum  of  all  the  supplements  should  be,  as  abc  ve,  380° 
and  if  this  result  is  not  obtained  there  is  error  somewhere. 


CRYSTALLOGRAPHY.  11 

The  reflecting  goniometer  affords  a  more  accurate  method  of 
measuring  crystals  that  have  lustre,  and  may  be  used  with  those  of 
minute  size.  The  principle  on  which  this  instrument  is  constructed 
will  be  understood  from  the  annexed  figure,  representing  a  crystal, 
whose  angle  a  b  c  is  required.  The  eye,  look' 
inof  at  the  face  of  the  crystal  b  c,  observes  a 
reflected  image  of  m,  in  the  direction  P  n.  On 
revolving  the  crystal  till  a  b  has  the  position  of 
b  c,  the  same  image  will  be  seen  again  in  tha 
same  direction  P  n.  As  the  crystal  is  turned, 
in  this  revolution,  till  a  b  d  has  the  present 
position  of  b  c,  the  angle  d  b  c  measures  the  number  of  degrees  through 
which  it  is  revolved.  But  d  b  c  subtracted  from  180C  equals  the  angle 
of  the  crystal  a  b  c.  The  crystal  is  therefore  passed,  in  its  revolution, 
through  a  number  of  degrees  equal  to  the  supplement  of  the  required 
angle. 

This  angle,  in  the  reflecting  goniometer  of  Wollaston,  is  measured 
by  attaching  the  crystal  to  a  graduated  circle  which  revolves  with  it, 
one  form  of  which  is  here  represented. 


C  is  the  graduated  circle.     The  wheel,  m,  is  attached  to  the  main 
ris,  and  moves  the  graduated  circle  together  with  the  adjusted  crystal. 


12  CBYSTALLOGKAPHY. 

The  wheel,  »,  is  connected  with  an  axis  which  passes  through  the 
main  axis  (which  is  hollow  for  the  purpose),  and  moves  merely  the 
parts  to  which  the  crystal  is  attached,  in  order  to  assist  in  its  adjust- 
ment. The  contrivances  for  the  adjustment  of  the  crystal  are  at  «,  #, 
c,  d,  k.  The  screws,  c,  d,  are  for  the  adjustment  of  the  crystal,  and  th« 
slides,  a,  £,  serve  to  centre  it. 

To  use  the  instrument,  it  may  be  put  on  a  stand  or  small  table,  with 
its  base  accurately  horizontal,  and  the  table  placed  in  front  of  a  win- 
dow, six  to  twelve  feet  off,  with  the  plane  of  its  circle  at  right  angles 
to  the  window.  A  dark  line  must  then  be  drawn  below  the  window, 
near  the  floor,  parallel  to  the  bara  of  the  window,  and  about  as  far 
from  the  eye  as  from  the  window-bar. 

The  crystal  is  attached  to  the  movable  plate  k  by  means  of  wax,  and 
BO  arranged  that  the  edge  of  intersection  of  the  two  planes  forming  the 
required  angle,  shall  be  in  a  line  with  the  axis  of  the  instrument. 
This  is  done  by  varying  its  situation  on  the  plate,  or  by  means  of  the 
adjacent  screws  and  slides. 

When  apparently  adjusted,  the  eye  must  be  brought  close  to  the 
crystal,  nearly  in  contact  with  it,  and  on  looking  into  a  face,  part  of 
the  window  will  be  seen  reflected,  one  bar  of  which  must  be  selected 
for  the  trial.  If  the  crystal  is  correctly  adjusted,  the  selected  bar 
will  appear  horizontal,  and  on  turning  the  wheel  n,  till  this  bar,  aa 
reflected,  is  observed  to  approach  the  dark  line  below  seen  in  a  direct 
view,  it  will  be  found  to  be  parallel  to  this  dark  line,  and  ultimately  to 
coincide  with  it.  The  eye  for  both  observations  should  be  held  in 
precisely  the  same  position.  If  there  is  not  a  perfect  coincidence,  the 
adjustment  must  be  altered  until  this  coincidence  is  obtained.  Con- 
tinue then  the  revolution  of  the  wheel  n.  till  the  same  bar  is  seen  by 
reflection  in  the  next  face,  and  if  here  there  is  also  a  coincidence  of 
the  reflected  bar  with  the  dark  line  seen  direct,  the  adjustment  is  com- 
plete ;  if  not,  alterations  must  be  made,  and  the  first  face  again  tried. 
In  an  instrument  like  the  one  figured,  the  circle  is  usually  graduated 
to  twenty  or  thirty  minutes,  and,  by  means  of  the  vernier,  minutes  and 
half  minutes  are  measured.  After  adjustment,  180°  on  the  arc  must 
be  brought  opposite  0,  on  the  vernier,  y>.  The  coincidence  of  the  bar 
and  dark  line  is  then  to  be  obtained,  by  turning  the  wheel  n.  When 
obtained,  the  wheel  m  should  be  turned  until  the  same  coincidence  ia 
observed,  by  means  of  the  next  fac$,  of  the  crystal.  If  a  line  on  the 
graduated  circle  now  corresponds  with  0  on  the  vernier,  the  angle  is 
immediately  determined  by  the  number  of  degrees  opposite  this  line. 
If  no  line  corresponds  with  0,  we  must  observe  wbich  line  on  the 
vernier  coincides  with  one  on  the  circle.  If  it  is  the  18th  on  the 
vernier,  and  the  line  on  the  circle  next  below  0  on  the  vernier  marki 
125°,  the  required  angle  is  125°  18'  ;  if  this  latter  line  marks  125 °  20  , 
the  required  angle  is  125°  38'. 

In  the  better  instruments  other  improved  methods  of  arrangemei;4 
are  employed  ;  and  in  the  best,  often  called  Mitscherlich' s  goniometer, 
because  first  devised  by  him,  there  are  two  telescopes,  one  for  passing 
a  ray  of  light  upon  the  adjusted  crystal,  having  crossed  hair  lines  in  its 
focus,  and  the  other  for  viewing  it,  also  with  a  hair  cross.  With  such 
an  arrangement,  the  window-bur  and  dark  line  are  unnecessary,  the 
hair  crosses  serving  to  fix  the  position  of  the  crystal,  and  the  telescopa 
that  of  the  eye.  If  the  crystal  is  perfect  in  its  planes,  ar4  the  adjust- 


CETSTALLOGRAPHY.  13 

ment  exact,  the  measurement,  with  the  best  instruments,  will  give  the 
angle  within  10". 

Other  goniometers  have  only  the  second  of  the  two  telescopes  just 
alluded  to,  as  is  the  case  in  the  figure  on  page  11.  This  telescope  gives 
a  fixed  position  to  the  eye  ;  and  through  it  is  seen  a  reflection  of  some 
distant  object,  which  may  be  even  a  chimney-top.  For  the  measure- 
ment the  object,  seen  reflected  in  the  two  planes  successively,  is 
brought  each  time  into  conjunction  with  the  hair  cross.  Exact  adjust- 
ment is  absolutely  essential,  and  with  an  instrument  having  the  two 
telescopes,  the  first  step  in  a  measurement  cannot  be  taken  without  it. 

Only  small,  well-polished  crystals  can  be  accurately  measured  by  the 
reflecting  goniometer.  If,  when  using  the  instrument  without  tele- 
scopes, the  faces  do  not  reflect  distinctly  a  bar  of  the  window,  the  flame 
of  a  candle  or  of  a  gas-burner,  placed  at  some  distance  from  the  crystal, 
may  be  used  by  observing  the  flash  from  it  with  the  faces  in  succession 
as  the  circle  is  revolved.  A  ray  of  sun-light  from  a  mirror,  received  on 
the  crystal  through  a  small  hole,  may  be  employed  in  a  similar  way.  But 
the  results  of  such  measurements  will  bo»  only  approximations.  With 
two  telescopes  and  artificial  light,  and  with  a  cross  slit  to  let  the  light 
pass  in  place  of  the  cross  hairs  of  the  first  of  the  above-mentioned  tele- 
scopes, this  light  cross  will  be  reflected  from  the  face  of  a  crystal  even 
when  it  is  not  perfect  in  polish,  and  quite  good  results  may  be  obtained. 


B.  STRUCTURE. — Structure  includes  cleavage,  a  characteristic 
of  crystals  intimately  connected  with  their  forms  and  nature. 
It  is  the  property,  which  many  crystals  have,  of  admitting  ot 
subdivision  indefinitely  in  certain  directions,  and  affording 
usually  even,  and  frequently  polished,  surfaces.  The  direction 
is  always  parallel  with  the  planes  of  the  axes,  or  with  others 
diagonal  to  these. 

The  ease  with  which  cleavage  can  be  obtained  varies  greatly 
in  different  minerals,  and  in  different  directions  in  the  same 
mineral.  In  a  few  species,  like  mica,  it  readily  yields  laminae 
thinner  than  paper,  and  in  this  case  the  cleavage  is  said  to  be 
eminent.  Others,  of  perfect  cleavage,  cleave  easily,  but  afford 
thicker  plates,  and  from  this  stage  there  are  all  grades  to  that 
in  which  cleavage  is  barely  discernible  or  difficult.  The  cleav- 
age surfaces  vary  in  lustre  from  the  most  brilliant  to  those  that 
are  nearly  dull.  When  cleavage  in  a  mineral  is  alike  in  two  or 
more  directions,  that  is,  is  attainable  in  these  directions  with 
equal  facility  and  affords  surfaces  of  like  lustre  and  character 
or  marking,  this  is  proof  that  the  planes  in  those  directions  are 
similar,  or  have  similar  relations  to  like  axes.  For  example, 
equal  cleavage  in  three  directions,  at  right  angles  to  one  another, 
shows  that  the  planes  of  cleavage  correspond  to  the  faces  of  the 
cube ;  so  equal  cleavage  in  two  directions,  in  a  prismatic  min- 
eral, shows  that  the  planes  in  the  two  directions  are  those  of  a 


CRYSTALLOGRAPHY. 


square  prism,  or  else  of  a  rhombic  prism ;  and  if  they  are  at 
right  angles  to  one  another  that  they  are  those  of  the  former. 
This  subject  is  further  illustrated  beyond. 


In  the  following  pages  (1)  the  Systems  of  Crystallization  and 
the  Forms  and  Structure  of  Crystals  are  first  considered ;  next, 
(2)  Compound,  or  Twin  Crystals;  and  then  (3)  Crystalline 
Aggregates. 


1.  SYSTEMS   OF  CRYSTALLIZATION:   FORMS 
AND  STRUCTURE  OF  CRYSTALS. 

The  forms  of  crystals  are  exceedingly  various,  while  the  sys- 
tems of  crystallization,  based  on  their  mathematical  distinctions, 
are  only  six  in  number.  Some  of  the  simplest  of  the  forma 
under  these  six  systems  are  the  prisms  represented  in  the  fol- 
lowing figures;  and  by  a  study  of  these  forms  the  distinctions 


3. 


4. 


of  the  six  systems  will  become  apparent.  These  prisms  are  all 
four-sided,  excepting  the  last,  which  is  six-sided.  In  them  the 
planes  of  the  top  and  bottom,  and  any  planes  that  might  be 
made  parallel  to  these,  are  called  the  based  planes,  and  the  sides 
the  lateral  planes.  An  imaginary  line  joining  the  centres  of 
the  bases  (c  in  figures  1  to  8)  is  called  the  vertical  axis,  and  the 


SYSTEMS    OF    CRYSTALLIZATION.  15 

diagonals  a  and  b,  drawn  in  a  plane  parallel  to  the  base,  are  the 
lateral  axes. 

Fig.  1  represents  a  cube.  It  has  all  its  planes  square  (like 
fig.  9),  and  all  its  plane  and  solid  angles,  right  angles,  and  the 
three  axes  consequently  cross  at  right  angles  (or,  in  other 

9.  10.  11.  12. 


noo 


words,  make  rectangular  intersections)  and  are  equal.  It  is  an 
example  under  the  first  of  the  systems  of  crystallization,  which 
system,  in  allusion  to  the  equality  of  the  axes,  is  called  the 
Isometric  system,  from  the  Greek  for  equal  and  measure. 

Fig.  2  represents  an  erect  or  right  square  prism  having  all  its 
plane  angles  and  solid  angles  rectangular.  The  base  is  square 
or  a  tetragon,  and  consequently  the  lateral  axes  are  equal  and 
rectangular  in  their  intersections  •  but,  unlike  a  cube,  the  verti- 
cal axis  is  unequal  to  the  lateral.  There  are  hence,  in  the  square 
prism,  axes  of  two  kinds  making  rectangular  intersections.  The 
system  is  hence  called,  in  allusion  to  the  two  kinds  of  axes,  the 
bimetric  system,  or,  in  allusion  to  the  tetragonal  base,  the  TQ 
tragonal  system. 

Fig.  3  represents  an  erect  or  right  rectangular  prism,  in 
which,  also,  the  plane  angles  and  solid  angles  are  rectangular. 
The  base  is  a  rectangle  (fig.  10),  and  consequently  the  lateral 
axes,  connecting  the  centres  of  the  opposite  lateral  faces,  are  un- 
equal and  rectangular  in  their  intersections ;  and,  at  the  same 
time,  each  is  unequal  to  the  vertical.  There  are  hence  three 
unlike  axes  making  rectangular  intersections ;  and  in  allusion 
to  the  three  unlike  axes,  the  system  is  called  the  Trimetric  sys- 
tem. It  is  also  named,  in  allusion  to  its  including  erect  prisms 
having  a  rhombic  base,  the  Orthorhombic  system,  orthos,  in 
Greek,  signifying  straight  or  erect. 

This  rhombic  prism  is  represented  in  fig.  4.  It  has  a  rhom- 
bic base,  like  fig.  11 ;  the  lateral  axes  connect  the  centres  of  the 
opposite  lateral  edges ;  and  hence  they  cross  at  right  angles  and 
are  unequal,  as  in  the  rectangular  prism.  This  right  rhombio 
prism  is  therefore  one  in  system  with  the  right  rectangular 
prism. 

Fig.    5   represents    another   rectangular    prism,   and   fig.   0 


16  CRYSTALLOGRAPHY. 

another  rhombic  prism  ;  but,  unlike  figs.  3  and  4,  the  prisms  are 
inclined  backward,  and  are  therefore  oblique  prisms.  The  lat- 
eral axes  (a,  b)  are  at  right  angles  to  one  another  and  unequal, 
as  in  the  preceding  system ;  but  the  vertical  axis  is  inclined  to 
the  plane  of  the  lateral  axes.  It  is  inclined,  however,  to  only 
one  of  the  lateral  axes,  it  being  at  right  angles  to  the  other. 
Hence,  of  the  three  angles  of  axial  intersection,  two  are  rec- 
tangular, namely  a  on  6,  and  c  on  b,  while  one  is  oblique,  ihat  is 
c  (the  vertical  axis)  on  a.  In  allusion  to  this  fact,  there  being 
only  one  oblique  angle,  this  system  is  called  the  Monoclinic  sys- 
tem, from  the  Greek  for  one  and  inclined. 

Fig.  7  represents  an  oblique  prism  with  a  rhomboidal  base 
(like  fig.  12).  The  three  axes  are  unequal  and  the  three  axial 
intersections  are  all  oblique.  The  system  is  called  the  Triclinia 
system,  from  the  Greek  for  three  and  inclined. 

Fig.  8  represents  a  six-sided  prism,  with  the  sides  equal,  and 
the  base  a  regular  hexagon.  The  lateral  axes  are  here  three  in 
number.  They  intersect  at  angles  of  60° ;  and  this  is  so, 
whether  these  lateral  axes  be  lines  joining  the  centres  of  oppo- 
site lateral  planes,  or  of  opposite  lateral  edges,  as  a  trial  will 
show.  The  vertical  axis  is  at  right  angles  to  the  plane  of  the 
three  lateral  axes,  inasmuch  as  the  prism  is  erect  or  right.  The 
base  of  the  prism  being  a  regular  hexagon,  the  system  is  called 
the  Hexagonal  system. 

The  systems  of  crystallization  are  therefore  : 

I.  The  ISOMETRIC  system  :  the  three  axes  rectangular  in  in- 
tersections ;  equal. 

II.  The  DIMETRIC  or  TETRAGONAL  system  :  the  three  axea 
rectangular  in  intersections;  the  two  lateral  axes  equal,  and 
unequal  to  the  vertical. 

III.  The  TRIMETRIO  or  ORTHORHOMBIC  system  :  the  three  axea 
rectangular  in  intersections,  and  unequal. 

IV.  The  MONOCJLINIC  system  :   only  one  oblique  inclination 
out  of  the  three  made  by  the  intersecting  axes ;  the  three  axea 
unequal. 

V.  The  TRICLINIC  system  :  all  the  three  axes  obliquely  inclined 
to  one  another,  and  unequal. 

VI.  The  HEXAGONAL  system  :  the  vertical  axis  at  right  angles 
to  the  lateral ;  the  lateral  .three  in  number,  and  intersecting  at 
angles  of  60°. 

These  six  systems  of  crystallization  are  based  on  mathemati- 
cal distinctions,  and  the  recognition  of  them  is  of  great  value 
in  the  study  and  description  of  crystals.  Yet  these  distinct iona 
are  often  of  feeble  importance,  since  they  sometimes  separate 


SYSTEMS    OF   CRYSTALLIZATION. 


17 


species  and  crystalline  forms  that  are  very  close  in  their  rela- 
tions. There  are  forms  under  each  of  the  systems  that  differ 
but  little  in  angles  from  some  of  other  systems  :  for  example, 
square  prisms  that  vary  but  slightly  from  the  cubic  form  ;  tri- 
clinic  that  are  almost  identical  with  monoclinic  forms ;  hexa- 
gonal that  are  nearly  cubic.  Consequently  it  is  found  that  the 
same  natural  group  of  minerals  may  include  both  trimetric  and 
monoclinic  species,  as  is  true  of  the  Hornblende  group  ;  or 
monoclinic  and  triclinic,  as  is  the  fact  with  the  Feldspar  group, 
and  so  on.  It  is  hence  a  point  to  be  remembered,  when  the 
affinities  of  species  are  under  consideration,  that  difference  in 
crystallographic  system  is  far  from  certain  evidence  that  any 
species  are  fundamentally  or  widely  unlike. 


L   THE  ISOMETRIC  SYSTEM. 

1.  Descriptions  of  Forms.     The  following  are  figures  of  some 
of  the  forms  of  crystals  under  the  isometric  system  : 


2. 


The  first  is  the  cube  or  hexahedron,  ai^eady  described.  Be- 
dides  the  three  cubic  axes,  there  are  equal  diagonals  in  two 
other  directions  ;  one  set  connecting  the  apices  of  the  diago- 
nally opposite  solid  angles,  four  in  number  (because  the  number 
of  such  angles  is  eight),  and  called  the  octahedral  axes  ;  and 
another  set  connecting  the  centres  of  the  diagonally  opposite 
2 


18  CRYSTALLOGRAPHY. 

edges,  six  in  number  (because  the  number  of  edges  is  twelve)f 
and  called  the  dodecahedral  axes. 

Fig.  2  represents  the  octahedron,  a  solid  contained  undef 
eight  equal  triangular  faces  (whence  the  name  from  the  Greek 
eight  and /ace),  and  having  the  three  axes  like  those  in  the  cube. 
Its  plane  angles  are  60°  ;  its  interfacial  angles,  that  is  the  incli- 
nation of  planes  1  and  1  over  an  intervening  edge  (usually  written 
1  A  1)  =  109°  28'  ;  and  1  on  1  over  a  solid  angle,  70°  32'. 

Fig.  3  is  the  dodecahedron,  a  solid  contained  under  twelve 
equal  rhombic  faces  (whence  the  name  from  the  Greek  for  twelve 
and  face).  The  position  of  the  cubic  axes  is  shown  in  the  fig- 
ure. It  has  fourteen  solid  angles ;  six  formed  by  the  meeting  of 
four  planes,  and  eight  formed  by  the  meeting  of  three.  The 
interfacial  angles  (or  i  on  an  adjoining  i)  are  120°  ;  i  on  i  over 
a  four-faced  solid  angle  =90°. 

Fig.  4  is  a  trapezohedron,  a  solid  contained  under  24  equal 
trapezoidal  faces.  There  are  several  different  trapezohedrons 
among  isometric  crystalline  forms.  The  one  here  figured,  which 
is  the  common  one,  has  the  angle  over  the  edge  -Z?,  131°  49', 
and  that  over  the  edge  (7,  146°  27'.  A  trapezohedron  is  also 
called  a  tetragonal  trisoctahedron,  the  faces  being  tetragonal 
or  four-sided,  and  the  number  of  faces  being  3  times  8  (tris, 
octo,  in  Greek). 

Fig.  5  is  another  trisoctahedron,  one  having  trigonal  or  three- 
sided  faces,  and  hence  called  a  trigonal  trisoctahedron.  Com- 
paring it  with  the  octahedron,  fig.  2,  it  will  be  seen  that  three 
of  its  planes  correspond  to  one  of  the  octahedron.  The  same  is 
true  also  of  the  trapezohedron. 

Fig.  6  is  a  tetrahexahedron,  that  is  a  4  X  6-faced  solid,  the 
faces  being  24  in  number,  and  four  corresponding  to  each  face 
of  the  cube  or  hexahedron  (fig.  1). 

Fig.  7  is  a  hexoctahedron,  that  is  a  6  X  8-faced  solid,  a  pyramid 
of  six  planes  corresponding  to  each  face  in  the  octahedron,  as  is 
apparent  on  comparison.  There  are  different  kinds  of  hexocta- 
hedrons  known  among  crystallized  isometric  species,  as  well  as 
of  the  two  preceding  forms.  In  each  case  the  difference  is  not 
in  number  or  general  arrangement  of  planes,  but  in  the  angles 
between  the  planes,  as  explained  beyond. 

But  these  simple  forms  very  commonly  occur  in  combination 
frith  one  another  ;  a  cube  with  the  planes  of  an  octahedron  and 
the  reverse,  or  with  the  planes  of  any  or  all  of  the  other  kinds 
above  figured,  and  many  others  besides.  Moreover,  all  stages 
between  the  different  forms  are  often  represented  among  the 
crystals  of  a  species.  Thus  between  the  cube  and  octahedron, 


ISOMETRIC    SYSTEM, 


19 


occur  the  forms  shown  in  figs.  8  to  11.  Fig.  12  is  a  cube; 
fig.  8  represents  the  cube  with  a  plane  on  each  angle,  equally 
inclined  to  each  cubic  face ;  9,  the  same,  with  the  planes  on  the 
angles  more  enlarged  and  the  cubic  faces  reduced  in  size ;  and 


8. 


then  10,  the  octahedron,  with  the  cubic  faces  quite  small ; 
and  fig.  11,  the  octahedron,  the  cubic  faces  having  disappeared 
altogether.  This  transformation  is  easily  performed  by  the 
student  with  cubes  cut  out  of  chalk,  clay,  or  a  potato.  It  shows 
the  fact  that  the  cubic  axes  (fig.  12)  connect  the  apices  of  the 
solid  angles  in  the  octahedron. 

Again,  between  a  cube  and  a  dodecahedron  there  occur  forma 
like  figs.  13  and  14  ;  fig.  12  being  a  cube,  fig.  13  the  same>  with 
planes  truncating  the  edges,  each  plane  being  equally  inclined 
to  the  adjacent  cubic  faces,  and  fig.  14  another,  with  these 
planes  on  the  edges  large  and  the  cubic  faces  small ;  and  then, 
when  the  cubic  faces  disappear  by  farther  enlargement  of  the 
planes  on  the  edges,  the  form  is  a  dodecahedron,  fig.  15.  The 
student  should  prove  this  transformation  by  trial  with  chalk  or 
Borne  other  material,  and  so  for  other  cases  mentioned  beyond* 
The  surface  of  such  models  in  chalk  may  be  made  hard  by  a 
coat  of  mucilage  or  varnish. 

Again,  between  a  cube  and  a  trapezohedron  there  are  the 
forms  17  and  18 ;  16  being  the  cube,  17,  cube  with  three  planes 
placed  symmetrically  on  each  angle  ;  1 8,  the  same  with  the 
cubic  faces  greatly  reduced  (but  also  with  small  octahedral  faces), 
and  19,  the  trapezohedron,  the  cubic  faces  having  disappeared. 


CRYSTALLOGRAPHY. 


Again,  fig.  20  represents  a  cube  with  three  planes  on  each 
angle,  which,  if  enlarged  to  the  obliteration  of  the  faces  of  tha 
cube,  become  the  trigonal  trisoetahedron,  fig.  21.  So  again,  fig. 


16. 


17, 


22  represents  a  cube  with  six  faces  on  each  angle,  which,  if  en« 
larged  to  the  same  extent  as  in  the  last,  would  become  the  lex* 
octahedron,  fig.  23. 

Again,  fig.  25  is  a  form  between  the  octahedron  (fig.  24)  and 


dodecahedron  (fig.  26)  ;  and  figs.  27  and  28  are  forms  between 
the  dodecahedron,  fig.  26,  and  trapezohedron,  fig.  29. 


ISOMETRIC    SYSTEM. 


21 


Again,  fig.  30  is  a  form  between  a  cube  (fig.  16)  and  a  tetra 
hexahedron,  fig.  31 ;  fig.  32,  a  form  between  an  octahedron,  fig. 
24,  and  a  tetrahexahedron,  fig.  31 ;  fig.  33,  a  form  between  ai» 


octahedron  and  a  trigonal  trisoctahedron,  fig.  34  ;  fig.  35,  a  form 
between  a  dodecahedron  (planes  i)  and  a  tetrahexahedron ;  fig. 


36,  a  form  between  the  dodecahedron  and  a  hexoctahedron, 
fig.  37. 

Fig.  38  represents  a  cube  with  planes  of  both  the  octahedron 
»nd  dodecahedron. 

2,  Positions  of  planes  with  reference  to  the  axes.    Lettering 

Of  figures. — The  numbers  by  which  the  planes  in  the  above  figures, 
and  others  of  the  work,  are  lettered,  indicate  the  positions  of  the  planes 
with  reference  to  the  axes,  and  exhibit  the  mathematical  symmetry 
And  ratios  in  crystallization.  In  the  figure  of  the  cube  (fig.  1)  the  three 
axes  are  represented  ;  the  lateral  semi-axis  which  meets  the  front 
planes  in  the  figure  is  lettered  «;  that  meeting  the  side  plane  to  the 
right  6,  and  the  vertical  axis  c,  and  the  other  halves  of  the  same  axes 
respectively  -«,  -&,  -c.  By  a  study  of  the  positions  of  the  planes  of  the 


22  CRYSTALLOGRAPHY. 

cube  and  other  forms  with  reference  to  these  axes,  tho  following  facti 
will  become  apparent. 

In  the  cube  (fig.  1)  the  front  plane  touches  the  extremity  of  axis  «, 
but  is  parallel  to  axes  b  and  c.  When  one  line  or  plane  is  parallel  to 
another  they  do  not  meet  except  at  an  infinite  distance,  and  hence  the 
sign  for  infinity  is  used  to  express  parallelism.  Employing  j,  the 
initial  of  infinity,  as  this  sign,  and  writing  c,  £,  a,  for  the  semi-axes  so 
lettered,  then  the  position  of  this  plane  of  the  cube  is  indicated  by  the 
expression  ie  :  ib  :  la.  The  top  and  side-planes  of  the  cube  meet  one 
axis  and  are  parallel  to  the  other  two,  and  the  same  expression  answers 
for  each,  if  only  the  letters  «,  6,  c,  be  changed  to  correspond  with  their 
positions.  The  opposite  planes  have  the  same  expressions,  except  that 
the  c,  &,  a  will  refer  to  the  opposite  halves  of  the  axes  and  be  -c,  ~b,  -a. 

In  the  dodecahedron,  fig.  15,  the  right  of  the  two  vertical  front  planes 
t.  meets  two  axes,  the  axes  a  and  b,  at  their  extremities,  and  is  parallel 
to  the  axis  c.  Hence  the  position  of  this  plane  is  expressed  by  ic  :  Ib  :  la. 
So,  all  the  planes  meet  two  axes  similarly  and  are  parallel  to  the  third. 
The  expression  answers  as  well  for  the  planes  i  in  figs.  13, 14,  as  for  that 
of  the  dodecahedron,  for  the  planes  have  all  the  same  relation  to  the  axes. 

In  the  octahedron,  fig.  11,  the  face  1,  situated  to  the  right  above, 
like  all  the  rest,  meets  the  axes  a,  b,  c,  at  their  extremities ;  so  that  the 
expression  Ic  :  Ib  :  la  answers  for  all. 

Again,  in  fig.  17  (p.  20)  there  are  three  planes,  2-2,  placed  symmet- 
rically on  each  angle  of  a  cube,  and,  as  has  been  illustrated,  these  are 
the  planes  of  the  trapezohedron,  fig.  19.  The  upper  one  of  the  planes 
2-2  in  these  figures,  when  extended  to  meet  the  axes  (as  in  fig.  19), 
intersects  the  vertical  c  at  its  extremity,  and  the  others,  a  and  6,  at 
twice  their  lengths  from  the  centre.  Hence  the  expression  for  the  plane 
is  Ic  :  2b  :  2a.  So,  as  will  be  found,  the  left  hand  plane  2-2  on  fig. 
17,  will  have  the  expression  2c  :  Ib  :  2a;  and  the  right  hand  one, 
2c  :  2b  :  la.  Further,  the  same  ratio,  by  a  change  of  the  letters  for  tho 
semi-axes,  will  answer  for  all  the  planes  of  the  trapezohedron. 

In  fig.  20  there  are  other  three  planes,  2,  on  each  of  the  angles  of  a 
cube,  and  these  are  the  planes  of  the  trisoctahedron  in  fig.  21.  The 
lower  one  of  the  three  on  the  upper  front  solid  angle,  would  meet  if 
extended,  the  extremities  of  the  axes  a  and  6,  while  it  would  meet  the 
vertical  axis  at  twice  its  length  from  the  centre.  The  expression 
2c  :  Ib  :  la  indicates,  therefore,  the  position  of  the  plane.  So  also, 
Ic  :  Ib  :  2a  and  Ic:  2b  :  la  represent  the  positions  of  the  other  two 
planes  adjoining ;  and  corresponding  expressions  may  be  similarly  3b- 
tained  for  all  the  planes  of  the  trisoctahedron. 

Again,  in  fig.  30,  of  the  cube  with  two  planes  on  each  edge,  and  in 
fig.  31,  of  the  tetrahexahsdron  bounded  by  these  same  planes,  the  left 
of  the  two  planes  in  the  front  vertical  edge  of  fig.  30  (or  the  corre- 
sponding plane  on  fig.  31)  is  parallel  to  the  vertical  axis  ;  its  intersections 
with  the  lateral  axes,  a  and  b,  are  at  unequal  distances  from  the  centre, 
expressed  by  the  ratio  2b  :  la.  This  ratio  for  the  plane  adjoining  on 
the  right  is  Ib  :  2a.  The  position  of  the  former  is  expressed  by  the 
ratio  ic  :  2b  :  la,  and  for  the  other  by  ic  :  Ib  :  2a.  Thus,  for  each  of 
the  planes  of  this  tetrahexahedron  the  ratio  between  two  axes  is  1  :  2, 
while  the  plane  is  parallel  to  the  third  axis. 

Again,  in  fig.,  22,  of  the  cube  with  six  planes  on  each  solid  angle,  and 
in  the  hexoctahedron  in  fig.  23,  made  up  of  such  planes,  each  of  the 
planes  when  extended  so  that  it  will  meet  one  axis  at  once  its  length 


ISOMETKIO    SYSTEM.  23 

from  the  centre,  will  meet  the  other  axes  at  distances  expressed  by  a 
constant  ratio,  and  the  expression  for  the  lower  right  one  of  the  sis; 
planes  will  be  Be  :  f b  :  la.  By  a  little  study,  the  expressions  for  the 
other  five  adjoining  planes  can  be  obtained,  and  so  also  those  for  all  the 
48  planes  of  the  solid. 

In  the  isometric  system  the  axes  a,  5,  c,  are  equal,  so  that  in  the 
general  expressions  for  the  planes  these  letters  may  be  omitted ;  the 
expressions  for  the  above  mentioned  forms  thus  become — 

Cube  (fig.  1),  a  :  1  :  i.  Tetrahexahedron  (fig.  5),  i :  1  :  3. 

Octahedron  (fig.  2),  1  :  1  :  1.  Trigonal  trisoctahedron  (fig.  6), 
Dodecahedron  (fig.  3),  1  :  1  :  a*.  2:1:1. 

Trapezohedron  (fig.  4),  2  :  1  :  2.  Hexoctahedron  (fig.  7),  3  :  1  :  $. 

Looking  again  at  fig.  17,  representing  the  cube  with  planes  of  the  trap- 
ezohedron, 2  :  1  :  2,  it  will  be  perceived  that  there  might  be  a  trap- 
ezohedron having  the  ratios  H  :  1  :  1|,  3:1:3,  4:1:4,  5:1:5, 
and  others;  and,  in  fact,  such  trapezohedrons  occur  among  crystals. 
So  also,  besides  the  trigonal  trisoctahedron  2:1:1  (fig.  21),  there 
might  be,  and  there  in  fact  is,  another  corresponding  to  the  expression 
8:1:1;  and  still  others  are  possible.  And  besides  the  hexoctahedron 
3  :  1  :  f  (fig.  23),  there  are  others  having  the  ratios  4:1:2,  4  :  1  :  $, 
5  :  1  :  f ,  and  so  on. 

In  the  above  ratios,  the  number  for  one  of  the  lateral  axes  is  always 
made  a  unit,  since  only  a  ratio  is  expressed ;  omitting  this  in  the  ex- 
pression, the  above  general  ratios  become  :  for  the  cube,  i  :  a';  for  the 
octahedron,  1:1;  dodecahedron,  1  :  i ;  trapezohedron,  2:2;  tetra- 
hexahedron, i  :  2 ;  trigonal-trisoctahedron,  2:1;  and  hexoctahedron, 
3  :  f .  In  the  lettering  of  the  figures  these  ratios  are  put  on  the  planes, 
but  with  the  second  figure,  or  that  referring  to  the  vertical  axis,  first. 
Thus  the  lettering  on  the  hexoctahedron  (fig.  23),  is  3-|;  on  the  trigonal 
trisoctahedron  (fig.  21)  is  2,  the  figure  1  being  unnecessary ;  on  the 
tetrahexahedron  (fig.  31),  i-2 ;  on  the  trapezohedron  (figs.  4  and  19), 
2-2;  on  the  dodecahedron  (fig.  15),  z;  on  the  octahedron,  1;  on  the 
cube,  a'-i,  in  place  of  which  II  is  used,  the  initial  of  hexahedron.  In  the 
printed  page  these  symbols  are  written  with  a  hyphen  in  order  to  avoid 
occasional  ambiguity,  thus  3-f ,  i-2,  2-2,  etc.  Similarly,  the  ratios 
fcr  all  planes,  whatever  they  are,  may  be  written.  The  numbers  are 
usually  small,  and  never  decimal  fractions. 

The  angle  between  the  planes  i-2  (or  a" :  1  :  2)  and  0,  in  fig.  30,  page 
21,  may  be  easily  calculated,  and  the  same  for  any  plane  of  the  series 
i-n  (i  :  1  :  ri).  Draw  the  right-angled  triangle,  A  D  C, 
as  in  the  annexed  figure,  making  the  vertical  side, 
C  D,  twice  that  of  A  C,  the  base ;  that  is,  give  them 
the  same  ratio  as  in  the  axial  ratio  for  the  plane.  If 
A'G=  1,  CD  =  2.  Then,  by  trigonometry,  making 
AG  the  radius,  1  :  R::2  :  tan  DAC]  or  1 :  fi::2:  cot 
ADC.  Whence  tan  DAG  =  cot  ADC  =  2.  By  ad- 
ding to  90°,  the  angle  of  the  triangle  obtained  by  work- 
ing the  equation,  we  have  the  inclination  of  the  basal 
plane  0,  or  the  0  on  the  opposite  side  of  the  plane  a*- 2, 
(faces  of  the  cube)  on  the  plane  i-2.  So  in  all  cases, 
whatever  the  value  of  ft,  that  value  equals  the  tangent 
of  the  basal  angle  of  the  triangle  (or  the  cotangent  of  the  angle  at  the 
vertex),  and  from  this  the  inclination  to  the  cubic  faces  is  directly  ob- 


24  CBYSTALLOGBAPHT. 

tained  by  adding  90°.  If  n  =  1,  then  the  ratio  is  1  :  1,  as  in  ACht 
and  each  angle  equals  45°,  giving  135°  for  the  inclination  on  eithel 
adjoining  cubic  face. 

Again,  if  the  angles  of  inclination  have  been  obtained  by  measure- 
ment, the  value  of  n  in  any  case  may  be  found  by  reversing  the  above 
calculation  ;  subtracting  90°  from  the  angle,  then  the  tangent  of  this 
angle,  or  the  cotangent  of  its  supplement,  will  equal  n,  the  tangents 
Varying  directly  with  the  value  of  n. 

la  the  case  of  planes  of  the  m  :  1  :  1  series  (including  1:1:1,  2:1: 
1,  etc.),  the  tangents  of  the  angle  between  a  cubic  face  in  the  same 
zone  and  theee  planes,  less  90°,  varies  with  the  value  of  m.  In  the 
case  of  the  plane  1  (or  1:1:1),  the  angle  between  it  and  the  cubic  face 
is  125°  16'.  Subtracting  90°,  we  have  35°  16'.  Draw  a  right-angled 
triangle,  OBC,  with  35°  16'  as  its  vertex  angle.  BO  has 
the  value  of  Ic,  or  the  semi-axis  of  the  cube.  Make 
DC=2BC.  Then,  while  the  angle  OBC  has  the  value 
of  the  inclination  on  the  cubic  face  less  90°  for  the  plane 
1:1:1,  ODC  has  the  same  for  the  plane  2:1:1.  Now, 
making  OC'the  radius,  and  taking  it  as  unity,  BG  is  the 
tangent  of  BOG,  or  cot  OBC .  SoDC  =  2BC  is  the  tan- 
gent of  DOC,  or  cot  ODC.  By  lengthening  the  side  CD 
(—  2B  C  or  2c)  it  may  be  made  equal  to  5BC  =  3c,  its 
value  in  the  case  of  the  plane  3:1:1;  or  to  4BC  —  4e, 
its  value  in  the  case  of  the  plane  4:1:1;  or  mBC  =  me 
for  any  plane  in  the  series  m  :  1  :  1 ;  and  since  in  all 
there  will  be  the  same  relation  between  the  vertical  and 
the  tangent  of  the  angle  at  the  base  (or  the  cotangent  of  the  angle  at 
the  vertex),  it  follows  that  the  tangent  varies  with  the  value  of  m. 
Hence,  knowing  the  value  of  the  angle  in  the  case  of  the  form  1 
(1:1:1),  the  others  are  easily  calculated  from  it. 

BG  being  a  unit,  the  actual  value  of  0(7  is  |  1/2,  or  |/jf,  it  being  half  the 
diagonal  of  a  square,  the  sides  of  which  are  1,  and  from  this  value  the 
angle  35°  16'  might  be  obtained  for  the  angle  OBC. 

The  above  law  (that  for  a  plane  of  the  m  :  1  :  1  series,  the  tangent  of 
its  inclination  on  a  cubic  face  lying  in  the  same  zone,  less  90°,  varies 
with  the  value  of  m,  and  that  it  may  be  calculated  for  any  plane 
m  :  1  :  1  from  this  inclination  in  the  form  1:1:1),  holds  also  for 
planes  in  the  series  m  :  2  :  1,  or  m  :  3  :  1,  or  any  m  :  n  :  1.  That  is, 
given  the  inclination  of  0  on  1  :  n  :  1,  its  tangent  doubled  will  be  Ctat 
of  2  :  n  :  1,  or  trebled,  that  of  3  :  n  :  1,  and  so  on;  or  halved,  it  will  be 
that  of  the  plane  £  :  n  :  1 ,  which  expression  is  essentially  the  same  i& 
I  :2n:  2. 

These  examples  show  some  of  the  simpler  methods  of  applying  iSia- 
thematics  in  calculations  under  the  isometric  system.  The  values  of 
the  axes  are  not  required  in  them,  because  a  =  b  =  c  —  1. 

3.  Hemihedral  Crystals.— The  forms  of  crystals  described 
above  are  called  holohedral  forms,  from  the  Greek  for  all  and 
face,  the  number  of  planes  being  all  that  full  symmetry  re- 
quires. The  cube  has  eight  similar  solid  angles — similar,  that 
**,  in  the  enclosing  planes  and  plane  angles.  Consequently  the 
l&vt  of  full  symmetry  requires  that  all  should  have  the  same 


ISOMETRIC    SYSTEM. 


25 


planes  and  the  same  number  of  planes  ;  and  this  is  the  general 
law  for  all  the  forms.  This  is  a  consequence  of  the  equality 
of  the  axes  and  their  rectangular  intersections. 

But  in  some  crystalline  forms  there  are  only  half  the  num- 
ber of  planes  which  full  symmetry  requires.  In  %.  39  a  cube 
ia  represented  with  an  octahedral  plane  on  half,  that  is,  four,  of 


39. 


the  solid  angles.  A  solid  angle  having  such  a  plane  is  diag- 
onally opposite  to  one  without  it.  The  same  form  is  represented 
in  fig.  40,  only  the  cubic  faces  are  the  smallest ;  and  in  fig.  41 
the  simple  form  is  shown  which  is  made  up  of  the  four  octahe- 
dral planes.  It  is  a  tetrahedron  or  regular  three-sided  pyra- 
mid. If  the  octahedral  faces  of  fig.  39  had  been  on  the  other 
four  of  the  solid  angles  of  the  cube,  the  tetrahedron  made  of 
those  planes  would  have  been  that  of  fig.  42  instead  of  fig.  41. 

Other  hemihedral  forms  are  represented  in  figs.  43  to  45  j  fig. 
43  is  a  hemihedral  form  of  the  trapezohedron,  fig.    4,  p.    7; 


fig,  44,  hemihedral  of  the  hexoctahedron,  fig.  7,  or  a  hemi-nex- 
octahedron.  Fig.  45  is  a  combination  of  the  tetrahedron  (plane 
1)  and  hemi-hexoctahedron. 

Tn  these  forms  figs.  41-44,  no  face  has  another  parallel  to  it; 
ami  consequently  they  are  called  inclined  hemihedrons. 

Fig.  46  represents  a  cube  with  the  planes  of  a  tetrahexahe- 
dron,  as  already  explained.  In  fig.  47,  the  cube  has  only  one 
of  the  plarves  i-2  on  each  edge,  and  therefore  only  twelve  in  all ; 


26 


CRYSTALLOGRAPHY. 


and  hence  it  affords  an  example  of  hemihedrism — a  kind  that  is 
presented  by  many  crystals  of  pyrite.     Fig.  48  is  the  hemihe- 


46. 


dral  form  resulting  when  these  twelve  planes  i-2  ave  extended 
to  the  obliteration  of  the  cubic  faces ;  and  fig.  49  is  another, 
made  of  the  other  twelve  of  these  planes.  Again, 
in  fig.  50,  a  cube  is  represented  having  only 
three  out  of  the  six  planes  of  fig.  22,  and  this 
is  another  example  of  hemihedrism.  These  kinds 
differ  from  the  inclined  hemihedrons  in  having 
opposite  parallel  faces,  and  hence  they  are  called 
parallel  hemihedrons. 

4.  Internal  Structure  of  Isometric  Crystals,  or  Cleavage. — 

The  crystals  of  many  isometric  minerals  have  cleavage,  or 
•*.  greater  or  less  capability  of  division  in  directions  situated 
symmetrically  with  reference  to  the  axes.  The  cleavage  direc- 
tions are  parallel  either  to  the  faces  of  the  cube,  the  octahe- 
dron, or  the  dodecahedron.  In  g'alenite  (p.  145)  there  is  easy 
cleavage  in  three  directions  parallel  to  the  faces  of  the  cube  ; 
in  fluonte  (p.  208),  in  four  directions  parallel  to  the  faces  of  the 
octahedron  ;  in  sphalerite  (p.  154),  in  six  directions  parallel  to 
the  faces  of  the  dodecahedron.  These  cleavages  are  an  impor- 
tant means  of  distinguishing  the  species. 

The  three  cubic  cleavages  are  precisely  alike  in  the  ease  with 
which  cleavage  takes  place,  and  in  the  kinds  of  surface  obtained  ; 
and  so  is  it  with  the  four  in  the  octahedral  directions,  and  the  six 
in  the  dodecahedral.  Occasionally  cleavages  of  two  of  these  sys- 
tems occur  in  the  same  mineral ;  that  is,  for  example,  parallel  to 
both  the  faces  of  the  cube  and  the  octahedron  ;  but  when  so, 
those  of  one  system  are  much  more  distinct  than  those  of  the 
other,  and  cleavage  surfaces  in  the  two  directions  are  quite  un- 
like as  to  smoothness  and  lustre. 

5.  Irregularities  of  Isometric  Crystals. — A  cube  has  its  faces 
precisely  equal,  and  so  it  is  with  each  of  the  form*  v<apresented 


ISOMETRIC    SYSTEM. 


27 


in  figs.  2  to  7.     This  perfect  symmetry  is  almost  never  found 
in  actual  crystals. 


61. 


62. 


53. 


I  H 


H 


A  cubic  crystal  has  generally  the  form  of  a  square  prism  (fig. 
51  a  stout  one,  fig.  52  another  long  and  slender),  or  a  rectangu- 
lar prism  (fig.  53).  In  such  cases  the  crystal  may  still  be 
known  to  be  a  cube  ;  because,  if  so,  the  kind  of  surface  and 
kind  of  lustre  on  the  six  faces  will  be  precisely  alike ;  and  if 
there  is  cubic  cleavage  it  will  be  exactly  equal  in  facility  in 
three  rectangular  directions  ;  or  if  there  is  cleavage  in  four,  or 
BIX,  directions,  it  will  be  equal  in  degree  in  the  four,  or  the  six, 
directions,  and  have  mutual  inclinations  corresponding  with  the 
angles  of  the  octahedron  or  dodecahedron ;  and  thus  the  crys- 
tal will  show  that  it  is  isometric  in  system. 

The  same  shortening  or  lengthening  of  the  crystal  often  dia- 


55. 


57. 


guises  greatly  the  octahedron,  dodecahedron,  and  other  forma, 
This  is  illustrated  in  the  following  figures :    Fig.  54  shows  the 


28 


CRYSTALLOGRAPHY. 


form  of  the  regular  octahedron;  55,  an  octahedron  lengthened 
horizontally ;  56,  one  shortened  parallel  to  one  cf  the  paira 
of  faces;  57,  one  lengthened  parallel  to  another  pair,  the 
ultimate  result  of  which  obliterates  two  of  the  faces,  and 
places  an  acute  solid  angle  in  place  of  each.  The  solid  ia 
then  six-sided,  and  has  rhombic  faces  whose  plane  angles  are 
120°  and  60°.  The  following  figures  illustrate  corresponding 
Changes  in  the  dodecahedron  (fig.  58).  In  fig.  59  the  dodeca- 


hedion  is  lengthened  vertically,  making  a  square  prism  with  four- 
sided  pyramidal  terminations.  In  60,  it  is  shortened  vertically. 
In  61  the  dodecahedron  is  lengthened  obliquely  in  the  direction 
of  an  octahedral  axis,  and  in  62  it  is  shortened  in  the  same 
Ji.'ection,  making  six-sided  prisms  with  trihedral  terminations. 

So  again  in  the  trapezohedron  there  are  equally  deceptive 
f 'rins  arising  from  elongations  and  shortenings  in  the  same  two 
directions. 

These  distortions  change  the  relative  sizes  of  planes,  but  not 
the  values  of  angles.  In  crystals  of  the  several  forms  repre- 
sented in  figs.  54  to  57,  the  inclinations  are  the  same  as  in  the 
regular  octahedron.  There  is  the  same  constancy  of  angle  in 
other  distorted  crystals. 


SYSTEMS   OF   CRYSTALLIZATION. 


Occasionally,  as  in  the  diamond,  the  planes  of  crystals  arc 
£onvex ;  and  then,  of  course,  the  angles  will  differ  from  the 
true  angle.  It  is  important,  in  order  to  meet  the  difficulties  in 
the  way  of  recognizing  isometric  crystals,  to  have  clearly  in  the 
mind  the  precise  aspoct  of  an  equilateral  triangle,  which  is  the 
shape  of  a  face  of  an  octahedron ;  the  form  of  the  rhombic  face 
of  the  dodecahedron ;  and  the  form  of  the  trapezoidal  face  of  a 
trapezohedron.  With  these  distinctly  remembered,  isometric 
crystalline  forms  that  are  much  obscured  by  distortion,  or  which 
show  only  two  or  three  planes  of  the  whole  number,  will  often 
be  easily  recognized. 

Crystals  in  this  system,  as  well  as  in  the  others,  often  have 
their  faces  striated,  or  else  rough  with  points.  This  is  gener- 
ally owing  to  a  tendency  in  the  forming  crystal  to  make  two 
different  planes  at  the  same  time,  or  rather  an 
os .'illation  between  the  condition  necessary  for 
making  one  plane  and  that  for  making  another. 
Fig.  63  represents  a  cube  of  pyrite  with  stri- 
ated faces.  As  the  faces  of  a  cube  are  equal, 
the  striations  are  alike  on  all.  It  will  be  noted 
that  the  striations  of  adjoining  faces  are  at  right 
angles  to  one  another.  The  little  ridges  of  the 
striated  surfaces  are  made  up  of  planes  of  the  pentagonal  dode- 
cahedron (fig.  49,  p.  26),  and  they  arise  from  an  oscillation  in 
the  crystallizing  conditions  between  that  which,  if  acting  alone, 
would  make  a  cube,  and  that  which  would  make  this  hemihe- 
dral  dodecahedron.  Again,  in  magnetite,  oscillations  between  the 
octahedron  and  dodecahedron  produce  the  striations  in  fig.  04. 


65. 


MAGNETITE. 


COMMON   SALT. 


Octahedral  crystals  of  fluoritc    often  occur  with  the  facoa 
made  up  of  evenly  projecting  solid  angles  of  a  cube,  giving 


30 


CRYSTALLOGRAPHY. 


them  rough  instead  of  polished  planes.     This  has  arisen  from 
oscillation  between  octahedral  and  cubic  conditions. 

In  some  cases  crystals  are  filled  out  only  along  the  diagonal 
planes.  Fig.  65  represents  a  crystal  of  common  salt  of  this 
kind,  having  pyramidal  depressions  in  place  of  the  regular  faces. 
Octahedrons  of  gold  sometimes  occur  with  three-sided  pyram- 
idal depressions  in  place  of  the  octahedral  faces.  Such  forma 
sometimes  result  when  crystals  are  eroded  by  any  cause. 


H.   DIMETRIC,    OR   TETRAGONAL   SYSTEM. 

1.  Descriptions  of  Forms.— In  this  system  (1)  the  axes  cross  at 
right  angles;  (2)  the  vertical  axis  is  either  longer  or  shorter  than 
the  lateral;  and  (3)  the  lateral  axes  are  equal. 

The  following  figures  represent  some  of  the  crystalline  forms. 
They  are  very  often  attached  by  one  extremity  to  the  support- 


APOPHYLLITE. 


Z1KCON. 


fnf  rock  and  have  perfect  terminating  planes  only  at  the  other, 
Square  prisms,  with  or  without  pyramidal  terminations,  square 
octahedrons,  eight-sided  prisms,  eight-sided  pyramids,  and  espe- 
cially combinations  of  these,  are  the  common  forms.  Since  the 
(atei-al  axes  are  equal,  the  four  lateral  planes  of  the  square 
prisms  are  alike  in  lustre  and  surface-markings.  For  the  same 
reason  the  symmetry  of  the  crystal  is  throughout  by  fours ;  that 
is,  the  number  of  similar  pyramidal  planes  at  the  extremity  iy 
cither  four  or  eight;  and  they  show  that  they  are  similar  by 


DniETBIC,  OR   TETRAGONAL    SYSTEM. 


31 


being  exactly  alike  in  inclination  to  the  basal  plane  as  well  aa 
\like  in  lustre. 

There  are  two  distinct  square  prisms.     In  one  (fig.  10)  the 


10. 


11. 


12. 


axes  connect  the  centres  of  the  lateral  faces.  In  the  other 
(tig.  12)  they  connect  the  centres  of  the  lateral  edges.  In  fig. 
11  the  two  prisms  are  combined;  the  figure  shows  that  the 
planes  of  one  truncate  the  lateral  edges  of  the  other,  the  inter- 
facial  angle  between  adjoining  planes  being  135°.  Figs.  2,  3, 
4, 7,  are  of  others  having  planes  of  both  prisms.  In  fig.  13  one 
prism  is  represented  within  the  other. 

Fig.  14  represents  an  eight-sided  prism,  and  fig.  15  a  combi- 
nation of  a  square  prism  (i-t)  with  an  eight-sided  prism  (i-2) 


14. 


15. 


hi* 


Another  example  of  this  is  shown  in  fig.  4,  and  also  in  fig.  9, 
the  planes  i-2  in  one,  and  i-3  in  the  other. 

The  basal  plane  in  these  prisms  is  an  independent  plane,  be- 
cause the  vertical  axis  is  not  equal  to  the  lateral,  and  hence  it 
almost  always  differs  in  lustre  and  smoothness  from  the  lateral. 

Like  the  square  prisms,  the  square  octahedrons  are  in  two 
series,  one  set  (fig.  16)  having  the  lateral  or  basal  edges  parallel 
to  the  lateral  axes,  and  these  axes  connecting  the  centres  of 
opposite  basal  edges,  and  the  other  (fig.  17)  having  them  diago- 
nal to  the  axes,  these  axes  connecting  the  apices  of  the  opposite 


32 


CRYSTALLOGRAPHY. 


solid  angles,  as  in  the  isometric  octahedron.  There  may  be,  on 
the  same  crystal,  faces  of  several  octahedrons  of  these  two  series, 
differing  in  having  their  planes  inclined  at  different  angles  to 


16. 


the  basal  plane.  In  figs.  5  and  7  there  is  one  of  these  pyra- 
mids terminating  the  prism,  and  in  figs.  6  and  8  the  planes 
of  two.  In  figs.  1  to  3  there  are  planes  of  the  same  octahe- 
dron, but  combined  with  the  basal  plane  O  ;  and  in  fig.  4  there 
are  planes  of  two,  with  0.  In  fig.  9  there  are  planes  of  the 
same  octahedron,  with  planes  of  a  square  prism  (i-i),  and  of  an 
eight-sided  prism  (i-2).  In  fig.  18  there  is  the  prism  i-i  com- 
bined with  two  octahedrons,  and  the  basal  plane  0 ;  and  in 
19  the  planes  of  one  octahedron  with  the  prism  I. 

Fig.  20  represents  an  eight-sided  double  pyramid,  made  of 


21. 


equal  planes,  equally  inclined  to  the  base  ;  and  fig.  21,  the 
planes  on  the  square  pri#m  i-i.  The  small  planes,  in  pairs,  on 
fig.  8,  are  of  this  kind.  In  fig.  22  the  small  planes  3-3  of 
fig.  8  occur  alone,  without  planes  of  the  four-sided  pyramids, 
and  therefore  make  the  eight-sided  pyramid,  3-3. 

This  solid  of  sixteen  planes  has  the  largest  number  of  similar 
planes  possible  in  the  dimetric  system,  while  the  largest  number 
in  the  isometric  system  (occurring  in  the  hexoctahedron)  is 
forty-eight. 


DIMETRIC,  OK   TETRAGONAL    SYSTEM.  33 

2.  Positions  of  the  Planes  with  reference  to  the  Axes.— Let- 
tering of  planes.  In  the  prism  fig.  10,  the  lateral  planes  are  parallel  to 
fche  vertical  axis  and  to  one  lateral  axis,  and  meet  the  other  lateral  axis 
at  its  extremity.  The  expression  for  it  is  hence  (c  standing  for  the 
vertical  axis  and  a,  b  for  the  lateral)  ic  :  ib  :  la,  i,  as  before,  standing 
for  infinity  and  indicating  parallelism.  For  the  prism  of  fig.  12,  the 
prismatic  planes  meet  the  two  lateral  axes  at  their  extremities,  and 
are  parallel  to  the  vertical,  and 

hence  the  expression  for  them  is  23. 

X5  :  \b  :  la.  In  the  annexed  figure 
the  two  bisecting  lines,  a  —a  and 
b  ~-b,  represent  the  lateral  axes; 
the  line  s  t  stands  for  a  section  of 
a  lateral  plane  of  the  first  of  these  ~b  • 
prisms,  it  being  parallel  to  one 
lateral  axis  and  meeting  the  othei 

at  its  extremity,  and  ab  for  that      - 

of  the  other,  it  meeting  the  two 
at  their  extremities. 

In  the  eight-sided  prisms  (figs.  14,  15),  each  of  the  lateral  planes  is 
parallel  to  the  vertical  axis,  meets  one  of  the  lateral  axes  at  its  extrem- 
ity, and  would  meet  the  other  axis  if  it  were  prolonged  to  two  or  three 
or  more  times  its  length.  The  line  ao,  in  fig.  23,  has  the  position  of  one 
of  the  eight  planes  ;  it  meets  the  axis  b  at  0,  or  twice  its  length  from 
the  centre  ;  and  hence  the  expression  for  it  would  be  ic  :  2b  :  la,  or, 
since  b  =  a,  ic  :  2  :  1,  which  is  a  general  expression  for  each  of  the  eight 
planes.  Again,  op  has  the  position  of  one  of  the  eight  planes  of  an- 
other such  prism  ;  and  since  Op  is  three  times  the  length  of  06,  the  ex- 
pression for  the  plane  would  be  ic  :  3  :  1.  So  there  may  be  other  eight- 
sided  prisms ;  and,  putting  n  for  any  possible  ratio,  the  expression 
ic  :  n  :  1  is  a  general  one  for  all  eight-sided  prisms  in  the  dimetric  sys- 
tem. 

A  plane  of  the  octahedron  of  fig.  16  meets  one  lateral  axis  at  its 
extremity,  and  is  parallel  to  the  other,  and  it  meets  the  vertical  axis  c 
at  its  extremity ;  its  expression  is  consequently  (dropping  the  letters  a 
and  £,  because  these  axes  are  equal)  Ic  :  i  :  I.  Other  octahedrons  in 
the  same  vertical  series  may  have  the  vertical  axis  longer  or  shorter 
than  axis  c ;  that  is,  there  may  be  the  planes  2c  :  t  :  1,  Sc  :  i  :  1, 
4c  :  i  :  1,  and  so  on  ;  or  \c  :  i  :  1,  £c  :  i  :  1,  and  so  on ;  or,  using  m  for 
any  coefficient  of  c,  the  expression  becomes  general,  me  :  i  :  1.  When 
m  =  0  the  vertical  axis  is  zero,  and  the  plane  is  the  basal  plane  0  of 
the  prism  ;  and  when  m  =  infinity,  the  plane  is  ic  :  i  :  1,  or  the  vertical 
plane  of  the  prism  in  the  same  series,  i-a,  fig.  10. 

The  planes  of  the  octahedron  of  fig.  17  meet  two  lateral  axes  at  their 
extremities,  and  the  vertical  at  its  extremity,  and  the  expression  for  the 
plane  is  hence  Ic  :  1  :  1.  Other  octahedrons  in  this  series  will  have  the 
tpression  me  :  1  :  1,  in  which  m  may  have  any  value,  not  a 
greater  or  less  than  unity,  as  in  the  preceding  case.  When  in 
this  series  m  —  infinity,  the  plane  is  that  of  the  prism  ic  :  1  :  1,  or  that 
of  fig.  12. 

In  the  case  of  the  double  eight-sided  pyramid  (figs.  20,  21,  22), 
the  planes  meet  the  two  lateral  axes  at  unequal  distances  from  the 
centre  ;  and  also  meet  the  vertical  axis.  The  expression  may  \x 


34:  CRYSTALLOGRAPHY. 

2o  :  2  :  1,  4<5  :  2  :  1,  5c  :  3  :  1,  and  so  on;  or,  giving  it  a  general  form, 

me  :  n  :  1. 

In  the  lettering  of  the  planes  on  figures  of  dimetric  crystals,  the  first 
number  (as  in  the  isometric  and  all  the  other  systems)  is  the  coefficient 
of  the  vertical  axis,  and  the  other  is  the  ratio  of  the  other  two,  and 
when  this  ratio  is  a  unit  it  is  omitted. 

Tke  expressions  and  the  lettering  for  the  planes  are  then  as  follows : 

Expressions.  Lettering. 

For  square  prisms j  J;     £  |  *  ;  J  ^  f 

For  eight-sided  prisms ic  :  n  :  I  i-n 

For  octahedron, {  ';    ™\{\\  <? 

For  double  eight-sided  pyramids,     me  :  n  :  I  m-n 

The  symbols  are  written  without  a  hyphen  on  the  figures  of  crystals. 
On  figure  14,  the  plane  i-n  is  that  particular  i-n  in  which  n  r=  2,  or  i-2. 
In  fig.  21  the  planes  of  the  double  eight-sided  pyramid,  m-n,  have 
m  =  1  and  n  =  2  (the  expression  being  1:2:1),  and  hence  it  is  lettered 
1-2.  In  fig.  8  and  in  fig.  22  it  is  the  one  in  which  m  =  3  and  n  =  3 
(the  expression  being  3:3:1),  and  hence  the  lettering  3-3. 

The  length  of  the  vertical  axis  c  may  be  calculated  as  follows,  pro- 
vided the  crystal  affords  the  required  angles : 

Suppose,  in  the  form  fig.  18,  the  inclination  of  0  on  plane  l-i  to  have 
been  found  to  be  130°,  or  of  iri  on  the  same  plane,  140°  (one  follows 
from  the  other,  since  the  sum  of  the  two,  as  has  been  explained,  is 
necessarih  370').  Subtracting  90°,  we  have  40°  for  the  inclination  of 
the  plane  on  the  vertical  axis  c,  or  50 D  for  the  same  on  the  lateral  axis? 
a,  or  the  basal  section,  [n  the  right-angled  triangle,  OBG,  the  angle 
OBG  equals  40°.  If  0  G  be  taken  as  a  =  1,  then  BG  will 
be  the  length  of  the  vertical  axis  c  •  and  its  value  may  be 
obtained  by  the  equation  cot  40°  =  BG,  or  tan  50°  =  BG. 
On  fig.  18  there  is  a  second  octahedral  plane,  lettered 
\-i,  and  it  might  be  asked,  Why  take  one  plane  rather 
than  the  other  for  this  calculation  ?  The  determination 
on  this  point  is  more  or  less  arbitrary.  Ifc  is  usual  to 
assume  that  plane  as  the  unit  plane  in  one  or  the  other 
series  of  octahedrons  (fig.  16  or  fig.  17)  which  is  of  most 
common  occurrence,  or  that  which  will  give  the  simplest 
symbols  to  the  crystalline  forms  of  a  species ;  or  that 
which  will  make  the  vertical  axis  nearest  to  unity ;  or 
that  which  corresponds  to  a  cleavage  direction. 

The  value  of  the  vertical  axis  having  been  thus  deter- 
Q  ined  from  \  i,  the  same  may  be  determined  in  like  manner  for  -J-*  in 
uKe  same  figure  (fig.  18).  The  result  would  be  a  value  just  half  that  of 
BC.  Or  if  there  were  a  plane  2-»,  the  value  obtained  would  be  twice 
BG,  or  BD  in  fig.  24;  the  angle  ODG  +  90°  would  equal  the  inclina- 
tion of  0  on  2-i.  So  for  other  planes  in  the  same  vertical  zone,  aa  3-», 
4-/,  or  any  plane  m-i. 
If  there  were  present  several  planes  of  the  series  m-i,  and  their  incli- 


35 

lations  to  the  basal  plane  O  were  known,  then,  after  subtracting  from 
the  values  90°,  the  cotangents  of  the  angles  obtained,  or  the  tangents 
of  their  complements,  will  equal  m  in  each  case  ;  that  is,  the  tangents 
(or  cotangents)  will  vary  directly  with  the  value  of  m.  The  logaritl  .m 
of  the  tangent  for  the  plane  1-i,  added  to  the  logarithm  of  2,  will 
equal  the  logarithm  of  the  tangent  for  the  plane  2-i,  and  so  on. 

The  law  of  the  tangents  for  this  vertical  zone  m-i  holds  for  the  planes 
of  all  possible  vertical  zones  in  the  dimetric  system.  Further,  if  the 
•qaare  prism  were  laid  on  its  side  so  that  one  of  the  lateral  planes  be- 
came the  base,  and  if  zones  of  planes  are  present  on  it  that  are  vertical 
with  refe;ence  to  this  assumed  base,  the  law  of  the  tangents  still  holds, 
with  onlj  this  difference  to  be  noted,  that  then  one  of  the  lateral  axea 
is  the  vertical.  It  holds  also  for  the  trimetric  system,  no  matter  which 
of  the  diametral  planes  is  taken  for  the  base,  since  all  the  axial  inter- 
sections are  rectangular.  It  holds  for  the  monoclinic  system  for  the 
zone  of  planes  that  lies  between  the  axes  c  and  b  and  that  between  the 
axes  a  and  b,  since  these  axes  meet  at  right  angles,  but  not  for  that 
between  c  and  a,  the  angle  of  intersection  here  being  oblique.  It  holds 
for  all  vertical  zones  in  the  hexagonal  system,  since  the  basal  plane  iu 
this  system  is  at  right  angles  to  the  vertical  axis.  But  it  is  of  no  use 
in  the  tridinic  system,  in  which  all  the  axial  intersections  are  oblique. 

The  value  of  the  vertical  axis  c  may  be  calculated  also  from  the  incli- 
nation of  0  on  1,  or  of  /on  1.  See  tig.  2,  and  compare  it  with  fig.  17. 
If  the  angle  /on  1  equals  140°,  then,  after  subtracting  90°,  we  have  50° 
for  the  basal  angle  in  the  triangle  0GB,  fig.  24  ;  or  for  half  the  inter- 
facial  angle  over  a  basal  edge—  edge  Z—  in  fig.  17.  The  value  of  Q 
may  then  be  calculated  by  means  of  the  formula 


by  substituting  50°  for  %Z  and  working  the  equation. 
For  any  octahedron  in  the  series  in,  the  formula  is 


Z  being  the  angle  over  the  basal  edge  of  that  octahedron.     If  m  •=  2, 
then  c  =  |  (tan  iZvi).     Further,  m  =  (tan  \Z  f£)  -f-  c. 

The  interfacial  angle  over  the  terminal  edge  of  any  octahedron  m 
may  be  obtained,  if  the  value  of  c  is  known,  by  the  formulas 

me  =•  cot  c  cos  e  =  cot  $X 

X  being  the  desired  angle  (fig.  17).     The  same  for  any  octahedron  m~i 
may  be  calculated  from  the  formulas 

me  =  cot  €  cos  e  =  cos  |  T  V  2 

Ir  being  the  desired  angle  (fig.  16). 

For  other  methods  of  calculation  reference  may  be  made  to  the  "  Text 
Book  of  Mineralogy,"  or  to  some  other  work  treating  of  mathematical 
crystallography. 

3.  Hemihedral  Forms.—  Among  the  few  hemihedral  forma 
nuder  the  dimetric  system  there  is  a  tetrahedron,  called  a  sphen* 


36 


CRYSTALLOGRAPHY. 


old  (figs.  25  or  26),  and  also  forms  in  which  only  half  of  the 
sixteen  planes  of  the  double  eight-sided  pyramid,  or  half  the 
eight  planes  of  an  eight-sided  prism — those  alternate  in  position 


are  present  (ligs.  27,  28).     In  fig.  27  the  absent  planes   are 

those  of  half  the  pairs  of  planes  ;  and  in  fig.  28  they  include 
one  of  each  of  the  pairs,  as  will  be  seen  on  comparing  these 
figures  with  fig.  21. 

4.  Cleavage. — In  this  system  cleavage  may  occur  parallel  to  the 
sides  of  either  of  the  square  prisms  ;  parallel  to  the  basal  plane  ; 
parallel  to  the  faces  of  a  square  octahedron ;  or  in  two  of  these 
directions  at  the  same  time.     Cleavage  parallel  to  the  base  and 
that  parallel  to  a  prism  are  never  equal,  so  that  such  prisms 
need  not  be  confounded  with  distorted  cubes. 

5.  Irregularities  in  Crystals. — The  square  prisms  are   very 
often  rectangular  instead  of  square,  and  so  with  the  octahedrons. 
But,  as  elsewhere  among  crystals,  the  angles  remain  constant. 
When  forms  are  thus  distorted,  the  four  prismatic  planes  will  have 
like  lustre  and  surface  markings,  and  thus  show  that  the  faces 
are  normally  equal  and  the   lateral  axes  therefore  equal.     If 
the  plane  truncating  the  edge  of  a  prism  makes  an  angle  of 
precisely  135°  with  the  faces  of  the  prism,  this  is  proof  that 
the  prism  is  square,  or  that  the  lateral  axes  are  equal,  since  the 
angle  between  a  diagonal  of  a  square  and  one  of  its  sides  is  45°, 
and  135°  is  the  supplement  of  45°. 

6.  Distinctions.  —The  dimetric  prisms  have  the  base  different 
in  lustre  from  the  sides,  and  planes  on  the  basal  edges  different 
in  angle  from  those  on  the  lateral,  and  thus  they  differ  frona 
isometric  forms.     The  lateral  edges  may  be  truncated,  and   the 
new  plane  will  have  an  angle  of  135°  with  those  of  the  prism, 
in  which  they  differ  from  trimetric  forms,  while  like  isometric. 
The  extremities  of  the  prism,  if  it  have  any  planes  besides  the 
basal,  will  have  them  in  fours  or  eights,  each  of  the  four,  or 
of  the  eight,  inclined  to  the  base  at  the   same  angle.     When 
there  is  any  cleavage  parallel  to  the  vertical  axis,  it  is  alike 


TRIMETRIC,  OR   ORTHORHOMBIC    SYSTEM.  37 

in  two  directions  at  right  angles  with  one  another.  The 
lateral  planes  of  either  square  prism  are  alike  in  lustre  and 
markings. 


III.  TRIMETRIC,  OR  ORTHORHOMBIC  SYSTEM. 

1.  Descriptions  of  Forms. — The  crystals  under  the  trimotrio 
eystem  vary  from  rectangular  to  rhombic  prisms  and  rhombic 
octahedrons,  and  include  various  combinations  of  such  forms. 
Figs.  1  to  7  are  a  few  of  those  of  the  species  barite,  and  figs.  8 
to  10  of  crystals  of  sulphur. 


4. 


BARITE. 


SULPnUH. 


Fig.  11  represents  a  rectangular  prism  (diametral  prism), 
and  fig.  12  a  rhombic  p.iism,  each  with  the  axes.  The  axes 
connect  the  centres  of  the  opposite  planes  in  the  former ;  but 
in  the  latter  the  lateral  axes  connect  the  centres  of  the  oppo- 
site edges.  Of  the  two  lateral  axes  the  longer  is  called  the 
nuicrodiagonal,  and  the  shorter  tne  br  achy  diagonal.  The  verti- 
cal section  containing  the  former  is  the  macrodiagonal  section 
and  that  containing  the  latter,  the  br  achy  diagonal  section. 

In  the  rectangular  prism,  fig.  11,  only  opposite  planes  are  alike, 
because  the  three  axes  are  unequal.  Of  these  planes,  that  oppo- 
site to  the  larger  lateral  axis  is  called  the  macropinacoid,  and 
that  opposite  the  shorter  the  brachypinacoid  (from  the  Greek  for 
long  and  short,  and  a  word  signifying  board  or  table). 


CRYSTALLOGRA  PUT. 


pair — that  is,  one  of  these  planes  and  its  opposite — is  called  a 
hemiprism . 

In  the  rhombic  prism,  fig.  12,  the  four  lateral  planes  are 
similar  olanes.     But  of  the  four  lateral  edges  of  the  prism  two 


11. 


12. 


are  obtuse  and  two  acute.  Fig.  13  represents  a  combination  of 
the  rectangular  and  rhombic  prisms,  and  illustrates  the  rela- 
tions of  their  planes.  Other  rhombic  prisms  parallel  to  the 
vertical  axis  occur,  differing  in  interfacial  angles,  that  is,  in  the 
ratio  of  the  lateral  axes. 

Besides  vertical  rhombic  prisms,  there  are  also  horizontal 
prisms  parallel  to  each  lateral  axis,  a  and  b.  In  fig.  2  the  narrow 
planes  in  front  (lettered  $i)  are  planes  of  a  rhombic  prism  parallel 
to  the  longer  of  the  lateral  axes,  and  those  to  the  right  (H)  are 
planes  of  another  parallel  to  the  shorter  lateral  axis.  In  fig.  6 
the  planes  are  those  of  these  two  horizontal  prisms.  Such 
prisms  are  called  also  domes,  because  they  have  the  form  of  the 
roof  of  a  house  (domus  in  Latin  meaning  house).  In  fig.  3 
these  same  two  domes  occur,  and  also  the  planes  (lettered  I)  of 
a  vertical  rhombic  prism.  Of  these  domes  there  may  be  many 
both  in  the  macrodiagonal  and  the  brachydiagonal  series,  differing 
in  angle  (or  in  ratio  of  the  two  intersected  axes).  Those  par- 
allel to  the  longer  lateral  axis,  or  the  macrodiagonal,  are  called 
macrodomes  ;  and  those  parallel  to  the  shorter,  or  brachydiag- 
onal, are  called  br  achy  domes. 

A  rhombic  octahedron,  lettered  1,  is  shown  in  fig.  8  ;  a  com- 
bination of  two,  lettered  1  and  -J,  in  tig.  9  ;  and  a  combination 
of  four,  lettered  1,  J,  -J-,  -J-,  in  fig.  10.  This  last  figure  contains 
also  the  planes  I,  or  those  o£  a  vertical  rhombic  prism;  the 
planes  1-&,  or  those  of  a  dome  parallel  to  the  longer  lateral  axis ; 
ihe  planes  14,  or  those  of  a  dome  parallel  to  the  shorter  lateral 
axis  ;  the  plane  0,  or  the  basal  plane  ;  the  plane  i-i,  or  the 
brachypinacoid ;  and  also  a  rhombic  octahedron  lettered  1-3. 

2.  Positions  of  Planes.  Lettering  of  Crystals. — The  notation 
is,  in  a  general  way,  like  that  of  the  diraetric  system,  but  with  differ- 
ences made  necessary  by  the  inequality  of  the  lateral  axes.  The  letter! 


TRIMKTRIC,  OR    ORTHORHOMBIO    SYSTEM.  39 

for  the  three  are  written  c  :  t>  :  a  ;  I  being  the  longer  lateral  and  a  the 
Bhortei  lateral.  In  place  of  the  square  prism  of  the  dimetric  system, 
i-i,  there  are  the  hemiprisms  i-i  and  a-i,  or  the  macropinacoid  and  brachy- 
pinacoid,  having  the  expressions  ic  :  ib  :  Id  and  ic  :_ll  :  id.  The  form/ 
is  the  rhombic  prism,  having  the  expression  ic  :  \6  :  \a,  corresponding 
to  the  square  prism  /  in  the  dimetric  system.  The  planes  i-n  or  i-n 
are  other  rhombic  vertical  prisms,  the  former  corresponding  to 
ic  :  nb  :  \a,  the  other  to  ic  :  \b  :  ua.  If  »  =  2,  the  plane  is  lettered 
either  i-2  or  t-S.  The  plane  1*3  has  the  expression  Ic  :  \b  :  3d.  m-n 
and  m-n  comprise  all  possible  rhombic  prisms  and  octahedrons,  and 
correspond  to  the  expressions  me  :  nb  :  Id  and  me  :  \.b  :  nu.  When  m  = 
infinity  they  become  i-fi  and  i-h,  or  expressions  for  vertical  rhombic 
prisms  ;  when  n  =  infinity  they  become  m-l  and  m-i,  or  expressions  for 
macrodomes  and  brachydomes. 

The  question  which  of  the  three  axes  should  be  taken  as  the  vertical 
axis  is  often  decided  by  reference  simply  to  mathematical  convenience. 
Sometimes  the  crystals  are  prominently  prismatic  only  in  one  direction, 
as  in  topaz,  and  then  the  axis  in  this  direction  is  made  the  vertical.  In 
many  cases  a  cleavage  rhombic  prism,  when  there  is  one,  is  made  the 
vertical,  but  exceptions  to  this  are  numerous.  There  is  also  no  general 
rule  for  deciding  which  octahedron  should  be  taken  for  the  unit  octahe- 
dron. But  however  decided,  the  axial  relations  for  the  planes  will  re- 
zuain  essentially  the  same.  In  fig.  10,  had  the  plune  lettered  |  been 
made  the  plane  1,  then  the  series,  instead  of  being  as  if  is  in  the  figure, 
1»  ij  i>  &•>  would  have  been  2,  1,  f,  f,  in  which  the  mutual  axial  rela- 
tions are  the  same. 

The  relative  values  of  the  axes  in  the  trimetric  system  may  be  calcu- 
lated in  the  same  way  as  that  of  the  vertical  axis  in  the  dimetric  sys- 
tem, explained  on  page  34.  The  law  of  the  tangents,  as  stated  on  page 
35,  holds  for  this  system. 

3.  Hemihedral  Forms. — Hemihedral  forms  are  not  common 
in  this  system.     Some  of  those  so  considered  have  been  proved 
to  owe  their  apparent  hemiliedrism  to  their  being  of  the  mono- 
clinic  system,  as  in  the  case  of  datolite  and  two  species  of  the 
fchondrodite  group.     In  a  few  kinds,  as,  for  example,  calaimne, 
one  extremity  of  a  crystal  differs  in  its  planes  from  the  other. 
Such  forms  are  termed  hemimorphic,  from  the  Greek  for  half 
and  form.     They  become  polar  electric  when  heated,   that  is, 
are  pyroelectric,  showing  that  this  heraimorpliism  is  connected 
with  polarity  in  the  crystal. 

4.  Cleavage. — Cleavage  may  take  place  in  the  direction   Df 
either  of  the  diametral  planes  (that  is,  either  face  of  the  rectan- 
gular prism)  ;  but  it  will  be  different  in  facility  and  in  the  sur- 
face afforded  for  each.     In  anhydrite,  however,  the  difference  is 
very  small.     Cleavage  may  also  occur  in  the  direction  of  the 
planes  of  a  rhombic  prism,  either  alone  or  in  conr.ection  with 
cleavage  in  other  directions.      It  also  sometimes  occurs,  as  in 
sulphur,  parallel  to  the  faces  of  a  rhombic  octal uxlron. 


4rO  CKYSTALLOGKAPH1. 

5.  Irregularities  in  Crystals. — The  crystals  almost  never  cor- 
respond  in  their  diametral  dimensions  with  the  calculated  axial 
dimensions.     They  are  always  lengthened,  widened,  shortened, 
or  narrowed  abnormally,  but  without  affecting  the  angles.      Ex- 
amples of  diversity  in  this  kind  of  distortion  are  given  in  figs. 
1  to  7,  of  barite. 

6.  Distinctions. — In  the  trimetric  system  the  angle  135°  doea 
not  occur,  because  the  three  axes  are  unequal.     There  are  pyra- 
mids of  four  similar  planes  in  the  system,  but  never  of  eight ; 
and  the  angles  over  the  terminal  edges  of  the  pyramids  are 
never  equal  as  they  are  in  the  dimetric  system.     The  rectangu- 
lar octahedron  of  the  trimetric  system  is  made  up  of  two  hori- 
zontal prisms,  as  shown  in  fig.  6,  and  is  therefore  not  a  simple 
form  ;  and  it  differs  from  the  octahedron  of  the  dimetric  sys- 
tem corresponding  to  it  (fig.    16,  p.  32)  in  having  the  angles 
over  the  basal  edges  of  two  values. 


IV.  MONOCLINIC  SYSTEM. 

1.  Descriptions  of  Forms. — In  this  system  the  three  axes  are 
unequal,  as  in  the  trimetric  system ;  but  one  of  the  axial  inter- 
sections is  oblique,  that  between  the  axis  a  ^vnd  the  vertical  axis 
c.  The  following  examples  of  its  crystalline  forms,  figs.  1  to  6, 
show  the  effect  of  this  obliquity.  On  account  of  it  the  front 
or  back  planes  above  and  below  the  middle  in  these  figures 
differ,  and  the  anterior  and  posterior  prismatic  planes  are  une- 
qually inclined  to  a  basal  plane. 


2. 


PYROXENE. 


HORNBLENDE. 


The  axes  and  their  relations  are  illustrated  in  figs.  7  and  8. 
Fig.  7  represents  an  oblique  rectangular  prism,  and  fig.  8 
an  oblique  rhombic.  The  former  is  the  diametral  prism,  like 
the  rectangular  of  the  trimetric  system.  The  axes  connect 
the  centre*  of  the  opposite  faces,  and  the  planes  are  of  three 


MONOCLINIO    SYSTEM.  41 

distinct  kinds,  being  parallel  to  unlike  axes  and  diametral  sec- 
tions. In  the  latter,  as  in  the  trimetoi:;  ihombic  prism,  the 
lateral  axes  connect  the  centres  of  the  opposite  sides.  More- 
over, this  rhombic  prism  may  be  reduced  to  the  rectangular  by 
the  removal  of  its  edges  by  planes  parallel  to  the  lateral  axes. 

6. 


MIBABILITB. 

The  axis  a,  or  the  inclined  lateral  axis  (inclined  at  an  oblique 
angle  to  the  vertical  axis  c),  is  called  the  clinodiagonal ;  and  the 
axis  6,  which  is  not  inclined,  the  ortJiodiagonaL  (from  the  Greek 
for  right,  or  rectangular).  The  vertical  section  through  tho 
former  is  called  the  dinodiagonal  section  /  it  is  parallel  to  the 
plane  i-l  (fig.  1-6).  The  vertical  section  through  the  latter  is 


iLe  orthodiagonal  section  '  it  is  parallel  to  planes  i-i.  Owing  to 
the  oblique  angle  between  a  and  c,  the  planes  above  a  differ 
in  their  relations  to  the  axes  from  those  below,  and  hence  comes 
the  difference  in  the  angle  they  make  with  the  basal  plane. 

The  halves  of  a  crystal  either  side  of  the  clinodiagonal  section 
— tho  vertical  section  through  a  and  c — are  alike  in  all  planes 
and  angles.  Another  important  fact  is  this  :  that  the  plane  i-l, 
or  that  parallel  to  the  clinodiagonal  section,  is  at  right  angles  not 
only  to  O  and  i-i,  but  to  all  planes  in  the  zone  of  O  and  i-i ' 


42  CRYSTALLOGBAPHT. 

that  is,  in  the  clinodiagonal  zone ;  and  this  is  a  consequence  of 
the  right  angle  which  axis  b  makes  with  both  axis  c  and  axis  cu 
The  plane  i-i  is  called  the  orthopinacoid,  it  being  parallel  to  the 
orthodiagonal ;  and  the  plane  i-l,  the  clinopinacoid,  it  being 
parallel  to  the  clinodiagonal. 

Vertical  rhombic  prisms  have  the  same  relations  to  the  lateral 
axes  as  in  the  trimetric  system.  Domes,  or  horizontal  rhombic 
prisms,  occur  in  the  orthodiagonal  zone,  because  the  vertical 
axis  c  and  the  orthodiagonal  b  make  right  angles  with  one 
another.  In  fig.  6  the  planes  1-i,  2-i  belong  to  two  such 
domes.  They  are  called  clinodomes,  because  parallel  to  the 
clinodiagonal. 

In  the  clinodiagonal  zone,  on  the  contrary,  the  planes  above 
and  below  the  basal  plane  differ,  as  already  stated,  and  hence 
there  can  be  no  orthodomes ;  they  are  hemiorthodomes.  Thus, 
in  fig.  6,  %-i,  l-i  are  planes  of  hemiorthodomes  above  i-i,  and 

—  J-i  is  a  plane  of  another  of  different  angle  below  i-i.     The 
plane,  and  its  diagonally  opposite,  make  the  hemiorthodome. 

The  octahedral  planes  above  the  plane  of  the  lateral  axes  also 
differ  from  those  below.  Thus,  in  tigs.  5  and  6,  the  planes  1,  1 
are,  in  their  inclinations,  different  planes  from  the  planes  — 1, 

—  1 ;  so  in  all  cases.    Thus  there  can  be  no  monoclinic  octahedrons 
— only  hemioctahedrons.     An  oblique  octahedron  is  made  up  of 
two  sets  of  planes;  that  is,  planes  of  two   hemioctahedrons. 
Such  an  octahedron  may  be  modelled  and  figured,  but  it  will 
consist  of  two  sets  of  planes  :  one  set  including  the  two  above 
the  basal  section  in  front  and  their  diagonally  opposites  behind 


(fig.  9),  and  the  other  set  including  the  two  below  the  basal  sec- 
tion and  their  diagonally  opposites  (fig.  10). 

A  heiuioctahedron,  since  it  consists  of  only  four  planes,  ia 
really  an  obliquely  placed  rhombic  prism,  and  very  frequently 
they  are  so  lengthened  as  to  be  actual  prisms. 


TRICLINIO    SYSTEM.  43 

2  Positions  of  Planes.    Lettering  of  Crystals On  account  oi 

the  obliquity  of  the  crystals,  the  planes  above  and  below  the  basal  sec- 
tion require  a  distinguishing  mark  in  their  lettering,  as  well  as  in  the 
mathematical  expressions  for  them.  One  set  is  made  minus  and  the 
other  plus.  The  plus  sign  is  omitted  in  the  lettering.  In  fig.  7  there 
are  above  the  basal  section  (or  above  i-i)  the  planes  1-z,  £-z,  1,  |,  but  bo- 
low  it,  —  $•-»',  — 1.  T he  plus  planes  are  those  opposite  the  acute  inter- 
section of  the  basal  and  orthodiagonal  sections,  and  the  minus  those 
opposite  the  obtuse.  No  signs  are  needed  for  planes  of  the  cliuodiago- 
nal  section,  since  they  are  alike  both  above  and  below  the  basal  sec- 
tion. 

The  distinction  of  longer  and  shorter  lateral  axis  is  not  available  :u 
this  system,  since  either  may  be  the  clinodiagonal.  The  distinction  of 
clinodiagonal  and  orthodiagonal  planes  is  indicated  by  a  grave  accent 
over  the  number  or  letters  referring  to  the  clinodiagonal.  The  lettering 
for  the  cliuodomes  on  fig.  6  is  l-l,  2-1 — the  i  (initial  of  infinite,  with 
the  accent)  signifying  parallelism  to  the  cfm<?diagonal.  The  hemiocta- 
hedrons,  1,  2,  etc.,  need  no  such  mark,  as  the  expression  for  them 
is  \c  :  1  b  :  id,  2c  :  Ib  :  Id,  the  planes  having  a  unit  ratio  for  d  and  b. 
But  the  plane  2-$,  in  fig.  5,  requires  it,  its  expression  being  2c  :  \b  :  2d\ 
the  fact  that  the  last  2  refers  to  the  clinodiagonal  is  indicated  by 
the  accent.  If  it  referred  to  the  orthodiagonal,  that  is,  if  the  expres- 
sion for  the  plane  were  2c  :  2b  :  Id,  it  would  be  written  2-2  without  the 
accent. 

3.  Cleavage.  — Cleavage  may  be  basal,  or  parallel  to  either  of 
the  other  diametral  sections,  or  parallel  to  a  vertical  rhombic 
prism,  or  to  the  planes  of  a  hemioctahedron  ;  or  to  the  planes  of 
a  clinodorne,  or  to  that  of  a  hemiorthodome.    If  occurring  in  two 
or  more  directions  in  any  species  it  is  always  different  in  degree 
in  each  different  direction,  as  in  all  the  other  systems. 

4.  Irregularities. — Crystals  of  this  system  may  be  elongated 
abnormally  in  the  direction   of  either  axis,  and  any  diagonal. 
The  hemiorthodomes  may  be  in  aspect  the  bases  of  prisms,  and 
the  hemioctahedrons  the  sides  of  prisms.     Which  plane  in  the 
zone  of  hemiorthodomes  should  be  made  the  base,  and  which  in 
the  series  of  hemioctahedrons  should  be  assumed  as  the  funda- 
mental prism  determining  the  direction  of  the  vertical  axis,  ia 
often,  decided  differently  by  different  crystallographers.      Con- 
venience of  mathematical  calculation  is  often  the  principal  point 
referred  to  in  order  to  reach  a  conclusion. 


V.  TRICLINIC   SYSTEM. 

1.  Descriptions  of  Forms. — In  the  triclinic  system  the  three 
axes  are  unequal  and  their  three  intersections  are  oblique,  and 
consequently  there  are  never  more  than  two  planes  of  a  kind  j 


44 


CRYSTALLOGRAPHY. 


that  is,  planes  having  the  same  inclinations  to  cither  diamotral 
section.     The  following  are  examples  : 


AXINITE. 


ANORTHITE. 


AMBLYGONITE. 


The  difference  in  angle  from  monoclinic  forms  is  often  very 
small.  This  is  true  in  the  Feldspar  family.  Fig.  2,  of  the 
feldspar  called  anorthite,  is  very  similar  in  general  form  to 
fig.  4,  of  orthoclase,  which  is  monoclinic.  This  is  still  more 
strikingly  seen  on  comparing  fig.  4  with  fig.  5,  representing 
a  crystal  of  oligoclase,  another  one  of  the  triclinic  feldspars.  The 


ORTHOCLASE. 


OLIGOCLASE. 


planes  on  the  two  are  the  same  with  one  exception;  but  there 
is  this  difference,  that  in  orthoclase,  as  in  all  monoclinic  crys- 
tals, the  angle  between  the  planes  0  and  i-l  (the  two  directionji 


HEXAGONAL   SECTION   OF   HEXAGONAL   SYSTEM.  45 

of  cleavage)  is  90° ;  and  in  oligoclase  and  the  other  triclinio 
feldspars  it  is  3°  to  5°  from  90°,  being  in  oligoclase  93°  50',  and 
in  anorthite  94°  10'.  This  difference  in  angle  involves  oblique 
intersections  between  the  axes  b  and  c,  and  c  and  a,  which  are 
rectangu  lar  in  moiioclinic  forms.  There  is  a  similarly  close  ro 
lation  be  JT^een  the  triclinic  form  of  rhodonite  and  that  of  pyrox- 
ene, and  a  resemblance  also  in  composition. 

The  diametral  prism  in  this  system  is  similar  to  fig.  7  on 
page  41,  under  the  monoclinic  system,  but  differs  in  having  the 
planes  all  rhomboidal  instead  of  part  rectangular.  The  form 
correspond  vug  to  the  oblique  rhombic  prism  of  the  monoclinic 
system  (fig.  8,  p.  41)  also  has  rhon«boidal  instead  of  rhombic 
planes ;  moreover,  the  two  prismatic  planes  have  unequal  in- 
clinations to  the  vertical  diametral  section,  and  are  therefore 
dissimilar  planes.  The  prism,  consequently,  is  made  of  two 
hemiprisms,  and  the  basal  plane  is  another,  making  in  all  three 
heiniprisms. 

2.  Cleavage. — Cleavage  takes  place  independently  in  differ- 
ent diametral  or  diagonal  directions.  In  the  triclinic  feldspars 
it  conforms  to  the  directions  in  orthoclase,  with  only  the  excep- 
tion arising  from  the  obliquity  above  explained. 


VI.   HEXAGONAL  SYSTEM. 

This  system  is  distinguished  from  the  others  by  the  charac- 
ter of  its  symmetry — the  number  of  planes  of  a  kind  around 
the  vertical  axis  being  a  multiple  of  3.  The  number  of  lateral 
axes  is  hence  3.  It  is  related  to  the  dimetric  system  in  having 
the  lateral  axes  at  right  angles  to  the  vertical  and  equal,  and  is 
hence  like  it  also  in  the  optical  characters  of  its  crystals.  Its 
hexagonal  prismatic  form  approaches  trimetric  crystals  in  the 
obtuse  angle  (120°)  of  the  prism,  some  trimetric  crystals  having 
in  angle  of  nearly  1 20°. 

Under  this  system  there  are  two  sections  : 

1.  The  HEXAGONAL  SECTION,  in  which  the  number  of  planes 
of  a  kind  around  each  vertical  axis  above  or  below  the  basal 
section  is  6  or  12. 

2.  The  RHOMBOHEDRAL  SECTION,  in  which   the   number    of 
planes  of  a  kind  around  each  half  of  the  vertical  axis,  above  rjr 
below  the  basal  section,  is  3  or  6 ;  and,  in  addition,  the  planes 
above  are  alternate  in  position  with  those  below.     The  forms 
are  mathematically  hemihedral  to  the  hexagonal,  Vut  not  so 
in  their  real  nature. 


CRYSTALLOGRAPHY. 


I.   HEXAGONAL   SECTION. 


1.  Description  of  Forms. — Figs.  1  to  3  represent  some  of  th« 
forms  under  this  section.     Figs.   2  and  3  show  only   one  ex- 


MIMETITE. 


BERYL. 


APATITE. 


fcremity;  and  such  crystals  are  seldom  perfect  at  both.  All 
exhibit  well  the  symmetry  by  sixes  which  characterizes  this 
section  of  the  hexagonal  system. 


7. 


/ 

/ 

^jj 

jj 

J*risms.  Under  this  system  there  are  two  hexagonal  prisms 
•lid  a  number  of  occurring  twelve-sided  prisms.  Fig.  4  repre- 
sents one  of  the  hexagonal  prisms,  with  its  axes — the  three 
lateral  connecting  the  centres  of  the  opposite  edges.  Tho 
lateral  angles  of  the  prism  are  120°.  If  the  lateral  edges  of 
this  prism  are  truncated,  as  in  the  figure  of  apatite  (fig.  3),  the 
truncating  planes,  i-2,  are  the  lateral  faces  of  another  similar 
hexagonal  prism,  in  which,  as  the  relations  of  the  two  show,  the 


HEXAGONAL    SECTION   OF   HEXAGONAI    SfSTEM. 


8. 


lateral  axes  connect  the  centres  of  the  opposite  lateral  faces. 
This  prism  is  represented  in  fig.  5. 

The  lateral  edges  of  the  hexagonal  prisms  occur  sometimes 
with  two  similar  planes  on  each  edge,  and  these  planes,  wheu 
extended  to  the  obliteration  of  the  hexagonal  prism,  make 
%  twelve-sided  prism.  These  two 
planes  are  seen  in  fig.  8,  along 
with  the  planes  I  of  the  hexago- 
nal prism,  and  1  of  a  double  six- 
sided  pyramid,  besides  the  basal 
plane  0. 

Double  pyramids.     The  double 
pyramids  are   of  three  kinds:   (1) 

A  series  of  sij:-sided,  whose  planes  belong  to  the  same  verti- 
cal zone  with  the  planes  I.  The  planes  of  two  such  pyramids 
(lettered  1,  2)  are  shown  in  figs.  1  and  2,  three  of  them  in  fig. 
3  (lettered  £,  1,  2),  and  one  in  fig.  7,  and  one  such  double 
pyramid,  without  combination  with  other  planes,  in  fig.  6. 
(2)  A  series  of  six-sided  double  pyramids,  whose  planes  are  iu 
the  same  vertical  zone  with  i-2,  examples  of  which  occur  on  fig. 
2  (plane  2-2)— on  fig.  3  (planes  1-2,  2-2,  4-2).  The  form  of  this 
double  pyramid  is  like  tha^epresented  in  fig.  6,  but  the  lateral 
axes  connect  the  centres  01  the  basal  edges.  The  double  six- 
sided  pyramid  is  sometimes  called  a  quartzoid,  because  it  occurs 
in  quartz.  (3)  Twelve-sided  double  pyramids.  Two  planes  of 
en ch  a  pyramid  are  shown  on  a  hexagonal  prism  in  fig.  9,  also  in 


fig.  2  (the  planes  3- j),  and  the  simple  form  consisting  of  such 
planes  in  fig.  10 — a  form  called  a  beryttoid,  as  the  planes  are 
common  in  beryl.  In  fig.  1 1  the  planes  1  bel  Mig  to  a  double 
six-sided  pyramid  ;  and  those  next  below  (of  which  three  are 
lettered  W)  to  a  double  twelve-sided  pyramid. 


CRYSTALLOGRAPHY. 


2.  Lettering  Of  Crystals.— The  prism  of  fig.  5  is  lettered  a-2,  be- 
cause it  is  parallel  to  the  vertical  axis,  and  has  the  ratio  of  1  :  2  between 
two  lateral  axes.     This  is  shown  in  the  annexed  figure,  which  repre- 
sents the  hexagonal  outline  of  tlie  prism 
i-2  circumscribing  that  of  the  prism  /. 
The  plane  i-2  is  produced  to  meet  axis 
«,  which  it  does  when  a  is  extended  to 
twice  its  length  ;  whence  the  ratio  for 
the  axes  a,  a',  is  1  :  2. 

The  numbers  1,  2,  on  the  double  hexa- 
gonal  pyramids  in  fig.  1  indicate  the 
relative   lengths  of   the   vertical    axis 
of  the  two  pyramids,  they  having  the 
same  1  :  1  ratio  of  the  lateral  axes ;  and 
so  in  figs.  2,  3,  and  others. 
The  lettering  on  the  pyramids  of  the  other  series  in  fig.  3,    1-2,    2-2, 
4-2,  indicates,  by  the  second  figure,  that  the  planes ^pxe  in  the  same 
vertical  zone  with  the  prismatic  plane  *-2,  and  by  the  first  figure  the  rel- 
ative lengths  of  the  vertical  axes. 

In  the  twelve-sided  prisms  such  ratios  as  &-f,  i-§,  £-£  occur.  The 
fraction  in  any  case  expresses  the  ratio  of  the  lateral  axes  for  the  par- 
ticular planes.  The  double  twelve-sided  pyramids  have  the  ratios  3-| 
(fig.  2),  4-ij-,  and  others.  Both  in  these  forms  and  the  twelve-sided 
prisms,  the  second  figure  in  the  lettering,  expressing  the  ratio  of  the 
lateral  axes,  has  necessarily  a  value  between  1  and  2. 

3.  Kemihedral  Forms. — Fig.  1  Represents  a  crystal  of  apa- 
tite in  which  there  are  two  sets  cf  planes,  o  (=3-|)  and  0'  (=- 
which  are  hemihedral,  only  half  of 

the  full  number  of  each  o  existing 

instead  of  all.     This  kind  of  hemi- 

hedrism  consists  in  the  suppression 

of  an  alternate  half  of  the  planes 

in    each    pyramid    of   the    double 

twelve-sided  pyramid  (fig.  10),  and 

in  the   suppressed    planes   of  the 

upper  pyramid  being  here  directly 

over  those  suppressed  in  the  lower 

pyramid.    If  the  student  will  shade 

oror  half  the  plai>3y  alternately  of 

the    two    pyramids,    putting    the 

shaded  planes  above  directly  over 

those  below,  he  will  understand  the  nature  of  the  hemihedrism. 

In  some  hemihedral  forms  the  suppressed  planes  of  the  upper 

pyramid   alternate    with    those   of  the  lower ;    but  this   kind 

occurs   only   in   the   rhombohedral   section   of  the   hexagonal 

system. 

4.  Cleavage. — Cleavage  is  usually  basal,  or  parallel  to  a  six 


APATITE. 


KHOMBOHEDRAL  SECTION  OF  HEXAGONAL  SYSTEM 


14. 


sided  pyramid.  Sometimes  there  are  traces  of  cleavage  parallel 
to  the  faces  of  a  six-sided  pyramid. 
5.  Irregularities  of  Crystal- 
Distortions  sometimes  disguise 
greatly  the  real  forms  of  hexagonal 
Crystals  by  enlarging  some  planes 
At  the  expense  of  others.  This  is 
illustrated  in  fig.  14,  representing 
the  actual  form  presented  by  a 
crystal  having  the  planes  shown 
in  fig.  13.  Whenever  in  a  prism 
the  prismatic  angle  is  exactly  120° 
or  150°,  the  form  is  almost  always 
of  the  hexagonal  system. 


2.   RHOMBOHEDRAL  SECTION. 


1.  Descriptions  of  Forms. — The  following  figures,  1  u>  17, 
represent  rhombohedral  crystals,  and  all  are  of  one  mineral,  cal- 
cite.  They  show  that  the  planes  of  either  end  of  the  crystal 
are  in  threes,  or  multiples  of  threes,  and  that  those  above  are 
alternate  in  position  with  those  below.  There  is  one  exception 


FIGURES   OF    CRYSTALS   OF    CALCITE. 

to  this  remark,  that  of  the  horizontal  or  basal  plane  0,  i~  figs. 
83  11,  13.      The  simple  rhombohedral  forms  include: 

1.  Mhombohedrons,  figs.  1  to  6.     These  forms  are  included 
under  six  equal  planes,  like  the  cube,  but  these  planes   sire 
4 


50 


CRYSTALLOGRAPHY. 


rhombic  ;  and  instead  of  having  twelve  rectang  liar  edges,  thej 
have  six  obtuse  edges  and  six  acute. 

2.   iScalenokedrons,  fig.  7.     Scaleuohedrons  are  really  double 
six-sided  pyramids ;  but  the  six  equal  faces  of  eaoh  extremity 


14. 


15. 


FIGURES  OP  CRYSTALS  OF   CALCITE. 

of  the  crystals  are  scalene  triangles,  and  are  arranged  in  three 
pairs ;  moreover  the  pairs  above  alternate  with  the  pairs  below ; 
the  edges  in  which  the  pairs  above  and  below  meet — that  is  the 
basal  edges — make  a  zig-zag  around  the  crystal. 

3.  Hexagonal  prisms,  jT,  fig.  8.  These  are  regular  hexagonal 
prisms,  having  angles  between  their  faces  of  120°. 

A  rhombohedron  has  two  of  its  solid  angles  made  up  of  three 
equal  plane  angles.  When  in  position  the  apex  of  one  of  these 
solid  angles  is  directly  over  that  of  the  other,  as  in  figs.  1  to  6, 
and  also  in  fig.  18,  and  the  line  connecting  the  apices  of  these 
angles  (fig.  18)  is  called  the  vertical  axis.  In  this  position 

18. 


the  rhombohedron  has  six  terminal  edges,  three  above  and 
three  below,  and  six  lateral  edges.  As  these  lateral  edges 
are  symmetrically  situated  around  the  centre  of  the  crystal,  the 
three  lines  connecting  the  centres  of  opposite  basal  edges  will 
These  lines  are  tha  lateral  axes  of  i-he 


cross  at  angles  of  60°. 


RUOMB01IKDKAL    GECTION    OF    HEXAGONAL    Si STEM.        51 


rhombohedron,  and  they  are  at  right  angles  to  the  vertical  axis. 
It  is  stated  on  page  45  that  rhombohedral  forms  are,  from  a 
mathematical  point  of  view,  hemi/iedral  under  the  hexagonal 
system.  The  rhombohedron,  which  may  be  considered  a  double 
three-sided  pyramid,  is  heuiihedral  to  the  double  six-sided  pyra- 
mid. Fig.  19,  representing  the  latter  foriif}lias  its  alternate 
faces  shaded  ;  suppressing  the  faces  shaded  the  form  would  le 
that  of  fig.  18  ;  and  suppressing,  instead  of  these,  the  faces  not 
shaded,  the  form  would  be  that  of  another  rhombohedron,  dif- 
fering only  in  position.  The  two  are  distinguished  as  plus  and 
rrdnus  rhombohedrons.  They  are  combined  in  figs.  20,  21, 
forms  of  quartz.  Khombohedrons  vary  greatly  in  the  length  of 
the  vertical  axis  with  reference  to  the  lateral.  Figs.  1,  2,  3,  and 
18  represent  crystals  with  the  vertical  axis  short,  and  figs.  4,  5, 
6  others  with  a  long  vertical  axis.  In  the  former  the  terminal 
sdges  are  obtuse  and  the  lateral  acute,  and  the  latter  have  the 
terminal  edges  acute  and  the  lateral  obtuse  ;  the  former  are 
called  obtuse  rhombohedrons,  and  the  latter  acute. 

The  cube  placed  on  one  solid  angle,  with  the  diagonal  between 
it  and  the  opposite  solid  angle  vertical,  is,  in  fact,  a  rhombohe- 
dron intermediate  between  obtuse  and  acute  rhombohedrons — 
the  edges  that  are  the  terminal  in  this  position,  and  those  thai 
are  the  lateral,  being  alike  rectangular  edges.  Fig.  3  has  nearlj 
the  form  of  a  cube  in  this  position. 

The  relation  of  one  series  of  scalenohedrons  to  the  v\\t  tri\to 
hedron  is  illustrated  in  fig.  22.  This  figure 
represents  a  rhombohedron  with  the  lateral 
edges  bevelled.  These  bevelling  planes  are 
those  of  a  scalenohedron,  and  the  outer  lines 
of  the  same  figure  show  the  form  of  that 
scalenohedron .  which  is  obtained  when  the 
bevelment  is  continued  to  the  obliteration 
of  the  rhombohedral  planes.  Fig.  14  repre- 
sents this  scalenohedron  with  the  rhombohe- 
dral planes  much  reduced  in  size.  Other 
scalenohedrons  result  when  the  terminal 
edges  are  bevelled,  and  still  others  from 
pairs  of  planes  on  the  angles  of  a  rhombohe- 
dron. 

The  scalenohedron  is  hemihedral  to  the 
tweVe-sided  double  pyramid  (fig.  23). 

Jn  the  hexagonal  system  the  three  verti- 
cal axial  planes  divide  the  space  about  the 
vertical  axis  into  six  sectors  (fig.  12,  p.  48). 


62  CRYSTALLOGRAPHY. 

The  twelve-sided  double  pyramid  has  in  each  pyramid  a  pair 
of  faces  for  each  sector  ;  that  is,  six  pairs  for  each  pyramid.  If 
now  the  three  alternate  of  these  pairs,  and  those  in  the  uppei 
pyramid  alternate  with  those  of  the  lower  (the  shaded  in  fig.  23), 
were  enlarged  to  the  obliteration  of  the  rest  of  the  planes,  the 
/Resulting  form  would  be  a  scalenohedron — a 
solid  with  three  pairs  of  planes  to  each  pyra- 
mid instead  of  six.  Such  is  the  mathematical 
relation  of  the  scalenohedron  to  the  twelve- 
sided  double  pyramid.  If  the  faces  enlarged 
were  those  not  shaded  in  fig.  23,  another 
scalenohedron  would  be  obtained  which  would 
be  the  minus  scalenohedron,  if  the  other  were 
designated  the  plus. 

Fig.  8  shows  the  relations  of  a  rhombohe- 
dron  to  a  hexagonal  prism.  The  planes  H 
replace  three  of  the  terminal  edges  at  each  base  of  the  prism, 
and  those  above  alternate  with  those  below.  The  extension 
of  the  planes  H  to  the  obliteration  of  those  of  the  prismatic 
planes,  I,  and  that  of  the  basal  plane  O,  would  produce  the 
rhombohedron  cf  fig.  1.  Figs.  9  and  10  represent  the  same 
prism,  but  with  terminations  made  by  the  rhombohedron  of  fig.  2. 
By  comparing  the  above  figures,  and  noting  that  the  planes 
of  similar  forms  are  lettered  alike,  the  combinations  in  the 
figures  will  be  understood.  Fig.  1 6  is  a  combination  of  the 
planes  of  the  fundamental  rhombohedron  jR,  with  those  of  an- 
other rhombohedron  4,  and  of  two  scalenohedrons  I3  and  I5. 
Fig.  17  contains  the  planes  of  the  rhombohedron  —  -j-,  with  those 
of  the  scalenohedron  I8,  and  those  of  the  prism  i.  These  figures, 
and  figs.  14,  22,  have  the  fundamental  rhombohedron  revolved 
60°  from  the  position  in  fig.  1,  so  that  two  planes  H  are  in  view 
above  instead  of  the  one  in  that  figure. 

2.  Lettering  of  Figures.— Figs.  1  to  6,  representing  rhomboho- 
3rons  of  the  species  calcite,  are  lettered  with  numerals,  excepting  fig.  1, 
la  fig.  1  the  letter  R  stands  for  the  numeral  1,  and  the  numerals  on  Ihtf 
others  represent  the  relative  lengths  of  their  vertical  axes,  the  lateral 
being  equal.  In  fig.  4  the  vertical  axis  is  twice  that  in  fig.  1  ;  in  fig.  6 
thirteen  times  ;  and  in  fig.  15  the  planes  lettered  16  are  those  of  a  rhom- 
bohedron whose  vertical  axis  is  sixteen  times  that  of  fig.  1.  The  rhom- 
bohedrons  of  figs.  1,  5,  6,  and  15  are  plus  rhombohedrons;  that  is,  they 
are  in  the  same  vertical  series ;  while  2  and  3  are  minus  rhombohe- 
drons, as  explained  above.  The  rhombohedron,  when  its  vertical  axis 
is  reduced  in  Length  to  zero,  becomes  the  single  basal  plane  lettered  0 
in  the  series.  If,  on  the  contrary,  the  vertical  axis  of  the  rbombohe- 
ibon  is  lengthened  to  infinity,  the  faces  of  the  rhombohedron  become 


RHOMBOHEDRAL    SECTION    OF    HEXAGONAL   SYSTEM.        53 


those  of  a  six-sided  prism.  This  last  will  be  seen  from  the  relations 
of  the  planes  It  to  Ion  fig.  8,  and  from  the  approximation  to  a  prismatic 
form  in  the  planes  16  of  fig.  15.  For  an  explanation  of  the  lettering 
of  other  planes  on  rhombohedral  crystals,  reference  must  be  made  to 
the  "  Text-Book  of  Mineralogy." 

3.  Hemihedrism.      Tetartohedrism.  —  Heniihedrism   occur* 
among  rhombohedral  forms,  similar  to  that  in  fig.  13,  page  48, 
except  that  the  suppressed  planes  of  one  pyramid  are  alternate 
with  those  of  the  other.     One  of  these  is 

represanted  in  fig.  24.  The  planes  C-J  are 
six  in  number  at  each  extremity,  and  are  so 
situated  that  they  give  a  spiral  aspect  to  the 
crystal.  If  these  planes  were  only  three  in 
number  at  each  extremity,  the  alternate 
,hree  of  the  six,  the  form  would  be  tetarto- 
hedral  to  the  double  six-sided  pyramid  ; 
that  is,  there  would  be  one-fourth  the  num- 
ber of  planes  that  exist  in  the  double  twelve- 
sided  pyramid,  or  6  planes  instead  of  24. 
Such  cases  of  hemihedrism  and  tetartohe- 
diism  are  common  in  crystals  of  quartz,  and 
when  existing,  the  crystals  are  said  to  be 
plagihedral,  from  the  Greek  for  oblique  and 
face.  In  some  crystals  the  spiral  turns  to  the 
right  and  in  others  to  the  left,  and  the  two  kinds  are  distin- 
guished as  right-handed  and  left-handed.  There  are  also  tetar- 
tohedral  forms  in  which  one  whole  pyramid  of  a  scalenohedron, 
or  of  a  rhombohedron,  is  wanting.  For  example,  in  crystals  of 
tourmaline  rhombohedral  planes,  and  sometimes  scalenohedral, 
may  occur  at  one  extremity  of  the  prism  and  be  absent  from 
the  other.  This  dissimilarity  in  the  two  extremities  of  a  crys- 
tal of  tourmaline  is  connected  with  pyro-electric  polarity  in  the 
mineral.  Three-sided  prisms,  hemihedral  to  the  hexagonal  prism, 
are  common  in  some  rhombohedral  species,  as  tourmaline. 

4.  Cleavage. — Cleavage  usually  takes  place  parallel  to  the 
faces  of  a  rhombohedron,  as  in  calcite,  corundum.     Not  uniVe- 

quently  the  rhombohedral  cleavage  is  wanting^ 
and  there  is  highly  perfect  cleavage  parallel  to 
the  basal  plane,  as  in  graphite,  brucite. 

5.  Irregularities  of  Crystals. — Distortions  oc- 
cur of  the  same   nature  with    those  tinder   the 
other  systems.      Some  examples  are  given  under 
quartz.      Some  rhombohedral  species,  as  dolomite, 
have  the  opposite  faces  convex  or  concave,  as  in  fig.  25. 


CRYSTALLOGRAPHY. 


Occasional  curved  crystals  occur,  as  in  fig.  26,  representing 
crystals  of  quartz,  and  fig.   2'/  of  a  crystal  of  chlorite.     The 


QUARTZ. 


CHLORITE. 


feathery  crystallizations  on  windows,  called  frost,  are  exampleH 
of  curved  forms  under  this  system. 


VII.   DISTINGUISHING  CHARACTERS   OF   THE    SEVERAL 
SYSTEMS   OF   CRYSTALLIZATION. 

1.  ISOMETRIC  SYSTEM. — (1)  There  may  be  symmetrical  groups 
of  4  and  8  similar  planes  about  the  extremities  of  each  cubic 
axis ;  and  of  3  or  6  similar  planes  about  the  extremities  of  each 
octahedral    axis.     (2)  Simple  holohedral  forms  may  consist  of 
6  (cube),  8  (octahedron),  12  (dodecahedron),  24  (trapezohedron, 
trigonal  trisoctahedron,  and  tetrahexahedron) ,  and  48  (hexoc- 
tahedron)  planes. 

2.  DIMETRIC  SYSTEM. — (1)  Symmetrical  groups  of  4  and  8 
similar   planes   occur   about  the    extremities    of   the   vertical 
axis  only.     (2)  Prisms  occur  parallel  only  to  the  vertical  axis; 
and  these  prisms  are  either  square  or  eight-sided.      (3)   The 
simple  holohedral  forms  may  consist  of  2  planes  (the  bases),  of 
4  planes  (square  prisms),  of  8  planes  (eight-sided  prisms  and 
aquare   octahedrons),   of  16  planes    (double   eight-sided    pyra- 
mids). 

3.  TRIMETRIC  SYSTEM. — ( 1 )  Symmetrical  groups  of  4  similar 
planes  may  occur  about  the  extremities  of  Cither  axis,   but 
those  of  one  axis  belong  equally  to  the  others.     (2)  The  prisms 
are  rhombic  prisms  only,  and  these  may  occur  parallel  to  either 
axis,  the  horizontal  as  well  as  the  vertical.     (3)   Simple  holo 


TWIN,  OE   COMPOUND   CRYSTALS.  55 

hedral  forms  may  consist  of  2  planes  (the  bases,  and  each  pair 
of  diametral  planes),  of  4  planes  (rhombic  prisms  in  the  three 
axial  directions),  and  of  8  planes  (the  rhombic  octahedrons). 
(4)  The  forms  may  be  divided  into  equal  halves,  symmetrical  in 
planes,  along  each  of  the  diametral  sections. 

4.  MONOCLINTC    SYSTEM.  —  (1)    No   symmetrical   groups   of 
similar  planes  ever  ocour  around  the  extremities  of  either  axis. 
(2)  The  prisms  are  rhombic  prisms,  and  these  can  occur  paral- 
lel only  to  the  vertical   axis  and  the  clinodiagonal.     (3)  The 
planes  occurring  in  vertical  sections  above  and  below  the  basal 
section,  either  in  front  or  behind,  are  all  unlike  in  inclination 
to  that  section,  excepting  the  prismatic  planes  in  the  ortho- 
diagonal  zone ;  in  other  words,  true  prisms  occur  in  no  vertical 
section  excepting  the  orthodiagonal.     (4)  Simple  forms  consist  of 
2  planes  (the  bases,  the  diametral  planes,  and  hemiorthodomes), 
of  4  planes  (rhombic  prisms  in  two  directions  and  hemioctahe- 
drons).      (4)  The  forms  may  be  divided  into  equal  and  similar 
halves  only  along  the  clinodiagonal  section.      No  interfacial 
angle  of  90°  occurs  except  between  the  planes  of  the  clinodiag- 
onal zone  and  the  clinopinacoid. 

5.  TRICLINIO  SYSTEM.  —  In   triclinic  crystals  there  are   no 
groups  of  similar  planes  which  include  more  than  2  planes,  and 
hence  the  simple  forms  consist  of  2  planes  only.     The  forms 
are  not  divisible  into  halves  having  symmetrical  planes.     There 
are  no  iuterfacial  angles  of  90°. 

(5.  HEXAGONAL  SYSTEM. — Symmetrical  groups  of  3,  6,  and  12 
similar  planes  may  occur  about  the  extremities  of  the  vertical 
axis.  (2)  Prisms  occur  parallel  to  the  vertical  axis,  and  are 
either  six  or  twelve-sided  (3  in  a  hemihedral  form)  and  equi- 
lateral. (3)  Simple  holohedral  forms  may  consist  of  2  planes 
(the  basal),  of  6  planes  (hexagonal  prism),  of  12  planes  (twelve- 
sided  prisms  and  double  six-sided  pyramids),  of  24  planes 
(double  twelve-sided  pyramids).  Simple  rhombohedral  forina 
may  consist  of  2  planes  (the  basal),  of  6  planes  (rhombohedrons), 
and  of  12  planes  (scalenonedrons) , 


2.  TWIN,  OR  COMPOUND   CBYSTAIS. 

Compound  crystals  consist  of  two  or  more  single  crystals, 
united  usually  parallel  to  an  axial  or  diagonal  section.  A  few 
are  represented  in  the  following  figures.  Fig.  1  represents  a 
crystal  of  snow  of  not  uufvequent  occurrence.  As  is  evident 


56 


CRYST  ALLOGRAPH  Y. 


to  the  eye,  it  consists  either  of  six  crystals  meeting  in  a.point, 
or  of  three  crystals  crossing  one  another ;  and  besides,  there  are 
numerous  minute  crystals  regularly  arranged  along  the  rays. 
Fig.  2  represents  a  cross  (cruciform)  crystal  of  staurolite,  vkic  k 


1. 


5. 


is  similarly  compound,  but  made  up  of  two  intersecting  crys- 
tals. Fig.  3  is  a  compound  crystal  of  gypsum,  and  fig.  4 
one  of  spinel.  These  will  be  understood  from  the  following 
figures. 

Fig.  5  is  a  simple  crystal  of  gypsum  ; 
if  it  be  bisected  along  a  b,  and  the  right 
half  be  inverted  and  applied  to  the  other, 
it  will  form  fig.  3,  which  is  therefore  a 
twin  crystal  in  which  one  half  has  a  re- 
verse position  from  the  other.  Fig.  6  is 
a  simple  octahedron ;  if  it  be  bisected 
along  the  plane  a  b  c  d  e,  and  the  upper 
half,  after  being  revolved  half  way 
around,  be  then  united  to  the  lower,  it 

will  have  the  form  in  fig.  4.  Both  of  these,  therefore,  are 
similar  twins,  in  which  one  of  the  two  component  parts  is 
reversed  in  position. 

Crystals  like  figs.  3  and  4  have  proceeded  from  a  compound 
nucleus  in  which  one  of  the  two  molecules  was  reversed  ;  and 
those  like  fig.  1,  from  a  nucleus  of  three  (or  six)  molecules 
Compound  crystals  of  the  kinds  above  described,  thus  differ 
from  simple  crystals  in  having  been  formed  from  a  nucleuK 
of  two  or  more  united  molecules,  instead  of  from  a  simple 
nucleus. 

Compound  crystals  _tre  generally  distinguished  by  their  -re-en- 
tering angles,  and  often  also  by  the  meeting  of  striae  at  an  angle 
along  a  line  on  a  surface  of  a  crystal,  the  line  indicating  the 
plane  of  junction  of  the  two  crystals. 

Compound  crystals  are  called  twolings,  threelings,  fourlings, 
according  as  they  consist  of  two,  three,  or  four  united  crystals. 


TWIN,   OR    COMPOUND    CRYSTALS. 


57 


Fig.  1  represents  a  threeling,  and  2,  3,  and  4,  twolings.  In  3 
and  4  the  combined  crystals  are  simply  in  contact  along  the 
plane  of  junction ;  in  2  they  cross  one  another;  the  former  are 
called  coidact-twins  and  the  latter  penetration-twins. 

Besides  the  above,  there  are  also  geniculated  crystals,  as  in 
tlj2  annexed  figure  of  a  crystal  of  rutile.  The  bending  has  here 
*tke«u  place  at  equal  distances  from  the  centre 
of  the  crystal,  and  it  must  therefore  have  been 
subsequent  in  time  to  the  commencement  of 
the  crystal.  jLhe  prism  began  from  a  simple 
molecule  ;  but  after  attaining  a  certain  length 
an  abrupt  change  of  direction  took  place.  The 
angle  of  geniculation  is  constant  in  the  same 
mineral  species,  for  the  same  reason  that  the 
interfacial  angles  of  planes  are  fixed  ;  and  it  is  such  that  a  cross 
section  directly  through  the  geniculation  is  parallel  to  the  posi- 
tion of  a  common  secondary  plane.  In  the  figure  given  the 
plane  of  geniculation  is  parallel  to  one  of  the  terminal  edges. 
In  rutile  the  geniculated  crystals  sometimes  repeat  the  bendings 
at  each  end  until  the  extremities  meet  to  form  a  wheel-like 
twin. 

In  some  species,  as  albite,  the  reversion  of  position  on  which 

this  kind  of  twin  depends,  takes  place  at  so  short  intervals  that 

the  crystal  consists  of  parallel  plates, 

8.  9.  each  plate  often   less    than    a    twen- 

tieth of  an  inch  in  thickness.  A  sec- 
tion of  such  a  crystal,  made  trans- 
verse to  the  plate,  is  given  in  tig.  8  ; 
without  the  twinning  the  section 
would  have  been  as  in  fig.  9.  Tiie 
plates,  as  the  figure  shows,  make  with 
one  another  at  their  edges  a  re-enter- 
ing angle  (in  albite  an  angle  of  172° 
48'),  and  hence  a  plane  of  the  albite 
crystal  at  right  angles  to  the  twin- 
ning direction,  is  covered  with  a  series  of  ridges  and  depressions 
which  are  so  minute  as  to  be  only  fine  striations,  sometimes 
requiring  a  magnifying  power  to  distinguish.  Such  striationa 
in  -ilbite  are  therefore  an  indication  of  the  compound  struc- 
ture. 

This  kind  of  twinning  is  owing  to  successive  changes  of 
polarity  in  the  molecules  as  the  enlargement  of  the  crystal 
went  forward.  It  occurs  in  all  the  tricliiiic  feldspars,  and  is  a 
means  of  distinguishing  them  from  orthoclase. 


58 


CRYSTALLOGRAPHY. 


In  some  twin  crystals  the  two  component  parts  of  the  crystal 
are  not  united  by  an  even  plane,  but  run 
into  one  another  with  great  irregularity. 
Cases  of  this  kind  occur  in  the  species  of 
quartz  in  twins  made  up  of  the  forms  M 
and  —R  (or  —1).  In  fig.  10  the  shaded 
parts  of  the  pyramidal  planes  are  of  the 
form  — 1,  and  the  non-shaded  parts  of 
R.  Each  of  the  faces  is  made  up  partly 
of  R  and  partly  of  —1.  The  limits  of 
the  two  are  easily  seen  on  holding  the 
crystal  up  to  the  light,  since  the  —  1 
portion  is  less  well  polished  than  the 
other.  In  this  crystal,  as  in  other  crys- 
tals of  quartz,  the  striatioiis  of  planes  * 
are  owing  to  oscillations  between  pyram- 
idal and  prismatic  planes  while  the  for 
mation  of  the  latter  was  in  progress. 


3.   CRYSTALLINE   AGGREGATES. 

The  crystalline  aggregates  here  included  are  the  simple,  not 
the  mixed ;  that  is,  they  are  those  consisting  of  crystalline  in- 
dividual? of  a  single  species. 

The  crystalline  individuals  may  be  (1)  distinct  crystals  ;  (2) 
fibres  or  columns ;  (3)  scales  or  lamellae ;  or  (4)  grains,  either 
cleavable  or  not  so. 

1.  Consisting  of  distinct  crystals. — The  distinct  crystal  may 
be  either  long  or  short  prismatic,  stout  or  slender  to  acicular 
(needle-like),  and  capillary  (hair-like)  ;  or  they  may  have  any 
other  forms  of  crystals.  They  may  be  aggregated  (a)  in  lines  ; 
(b)  promiscuously  with  open  spaces  ;  (c)  over  broad  surfaces ; 
(d)  about  centres.  The  various  kinds  of  aggregates  thus  made 
ure : 

a.  Filiform. — Thread-like  lines  of  crystals,  the  crystals  often 
not  well  defined. 

b.  Dendritic. — Arborescent  slender  spreading  branches,  some- 
what plant-like,  made  up  of  more  or  less  distinct  crystals,  as  in 
the  frost  on  windows,  and  in  arborescent  forms  of  native   cop- 
per, silver,  gold,  etc. 

Fig.  1 1  represents,  much  magnified  an  arborescent  form  of 
magnetite  occurring  in  mica  at  Pennsbury,  in  Pennsylvania. 
A  rborescent  delineations  over  surfaces  of  rock  are  Msually  called 


CRYSTALLINE   AGGREGATES. 


59 


it. 


dtndrites.  They  have  been  formed  by  crystallization  from  a 
solution  of  mineral  matter  which  has  entered  by  some  crack  and 
spread  between  the  layers  of 
the  rock.  They  are  often 
black,  and  consist  of  oxide 
of  manganese  ;  others,  of  a 
brownish  color,  are  made  of 
limonite ;  others,  of  a  red- 
dish black  or  black  color,  of 
hematite.  Moss-like  forms 
also  occur,  as  in  moss  agate. 

c.  Reticulated.  —  Slender 
prismatic  crystals  promiscu- 
ously    crossing,    with     open 
spacings. 

d.  Divergent. — Free  crys- 
tals radiating  from  a  central 
point. 

e.  Drusy. — A  surface  is  drusy  when  made  up  of  the  extremi- 
ties of  small  crystals. 

2.   Consisting  of  columnar  individuals. 

a.  Columnar,  when  the  columnar  individuals  are  stout. 

b.  Fibrous,  when  they  are  slender. 

c.  Parallel  fibres,  when  the  fibres  are  parallel. 

d.  Radiated,    when    the    columns    or    fibres    radiate    from 
centres. 

e.  Stellated,  when   the   radiations  from  a  centre  are    equal 
around,  so  as  to  make  star-like  or  circularly-radiated  groups. 

f.  Globular,  when  the  radiated  individuals  make  globular  or 
hemispherical  forms,  as  in  wavellite. 

y.  Botryoidal)  when  the  globular  forms  are  in  groups,  a  lit- 
tle like  a  bunch  of  grapes.  The  word  is  from  the  Greek  for  a 
bunch  of  grapes. 

k.  Mammillary,  having  a  surface  made  up  of  low  and  broad 
prominences.  The  term  is  from  the  Latin  mammilla,  a  little 
teat. 

L  Coralloidal,  when  in  open-spaced  groupings  of  slender 
stems,  looking  like  a  delicate  coral.  A  result  of  successive  ad- 
ditions at  the  extremity  of  a  prominence,  lengthening  it  into 
cylinders,  the  stems  generally  having  a  faintly  radiated  struc- 
ture. 

Specimens  of  all  these  varieties  of  columnar  structure,  except- 
ing the  last,  often  have  a  druay  surface,  the  fibres  or  column! 
ending  in  projecting  crystals. 


60  CRYSTALLOGRAPHY. 

3.  Consisting  of  scales  or  lamellae. 

a.  Plumose,   having   a   divergent  arrangement  of  scales,  aa 
seen  on  a  surface  of  fracture;  e.  g.,  plumose  mica. 

b.  Lamellar,  tabular ',  consisting  of  flat  lamellar  crystalline  in- 
dividuals, superimposed  and  adhering. 

c.  Micaceous,  having  a  thin  fissile  character,  due  to  the  aggi» 
gation  of  scales  of  a  mineral   which,  like  mica,  has  eminuai 
cleavage. 

d.  Septate,   consisting  of  openly-spaced  intersecting  tabular 
individuals  ;  also  divided  into  polygonal  portions  by  reticulat- 
ing veins  or  plates.     A  septarium  is  a  concretion,  usually  flat- 
tened  spheroidal  in  shape,  the  solid  interior  of  which  is  inter- 
sected by  partitions ;  these  partitions  are  the  fillings  of  cracks 
in  the  interior  that  were  due  to  contraction  on  drying.     When 
the  surface  of  such  septate  concretions  has  been  worn  off,  they 
often  have  the  appearance  of  a  turtle's  back,  and  are  sometimes 
taken  for  petrified  turtles. 

4.  Consisting  of  grains.      Granular  structure.     A  massive 
mineral   may  be   coarsely  granular   or  finely  granular,  as  in 
varieties  of  marble,  granular  quartz,  etc.      It  is  termed  saccha- 
roidal  when  evenly  granular,  like  loaf  sugar.      It  may  also  be 
cryptocrystalline,  that  is,   having  no  distinct  grains  that  can. 
be  detected  by  the  unaided  eye,  as  in  flint.     The  term  crypto- 
crystalline  is  from  the  Greek  for  concealed  crystalline.     Aphani- 
tic,  from  the  Greek  for  invisible,  has  the  same  signification.    The 
term  ceroid  is  applied  when  this  texture  is  connected  with  a 
waxy  lustre,  as  in  some  common  opal. 

Under  this  section  occur  also  globular,  botryoidal,  and  inam- 
millary  forms,  as  a  result  of  concretionary  action  in  which  no 
distinct  columnar  interior  structure  is  produced.  They  are 
called  pisolitic  when  in  masses  consisting  of  grains  as  large  as 
peas  (from  the  Latin  pisum,  a  pea),  and  oolitic  when  the  grains 
are  not  larger  than  the  roe  of  a  fish,  from  the  Greek  for  egg. 

5.  Forms   depending    on  mode  of  deposition. — Besides  the 
above,  there  are  the  following  varieties  which  have  ccme  from 
mode  of  deposition  : 

a.  Stalactitic,  having  the  form  of  a  cylinder,  or  cone,  haLg- 
ing  from  the  roofs  of  cavities  or  caves.  The  term  stalactite  is 
usually  restricted  to  the  cylinders  of  carbonate  of  calci  im  hanging 
from  the  roofs  of  caverns ;  but  other  minerals  are  said  to  have 
a  stalactitic  form  when  resembling  these  in  their  general  shape 
and  origin.  Chalcedony  and  brown  iron  ore  are  often  stalacti- 
tic. Interiorly  the  structure  may  be  either  granular,  radiatelj 
fibvo'ls,  or  concentric. 


CRYSTALLINE    AGGREGATES.  61 

6,  Concentric. — When  consisting  of  lamellae,  lapping  one 
ovei  another  around  a  centre,  a  result  of  successive  concretion- 
ary aggregations,  as  in  many  concretionary  forms,  most  pisolite, 
part  of  oolite,  some  stalactites,  etc. 

c.  Stratified,  consisting  of  layers,  as  a  result  of  deposition : 
e.  g  ;  sc  me  travertine,  or  tufa. 

d.  Jiznded  /  color-stratified.     Like  stratified  in  origin,  but 
the  layers  usually  indicated  only  by  variations  in  color ;  the  band- 
ing is  shown  in  a  transverse  section  :  e.  g.,  agate,  much  stalag- 
mite, riband  jasper. 

e.  Geodes. — When  a  cavity  has  been  lined  by  the  deposition 
of  mineral  matter,  but  not  wholly  filled,  the  enclosing  mineral 
is  called  a  geode.     The  mineral  is  often  banded,  owing  to  the 
successive   depositions  of  the  material,  and  frequently  has  its 
inner  surface  set  with  crystals.     Agates  are  often  slices  or  frag- 
ments of  geodes. 

6.  Forms  derived  from  the  crystals  of  other  minerals.  Pseu- 
domorphs. — Crystalline  aggregates,  especially  the  granular, 
sometimes  have  forms  derived  from  the  crystals  of  other 
minerals  either 

(1)  Because  a  result  of  cotemporaneous  removal  and  substi* 
tution  ;   or 

(2)  Because  a  result  of  the  alteration  of  such  crystals ;  or 

(3)  Because  filling  spac.es   that  had  been   left   unoccupied  in 
consequence  of  previous  removal. 

For  example.  Crystals  occur  having  the  forms  of  calcite 
(calcium  carbonate,  or  "  carbonate  of  lime  "),  but  consisting  of 
quartz  or  silica.  They  were  made  from  calcite  crystals  by  the 
action  of  some  solution  containing  silica,  the  solution  dissolving 
away  the  calcite  and  depositing  at  the  same  time  silica  or  quartz. 
Specimens  occur  showing  all  stages  in  the  change  from  the  ear- 
liest in  which  the  calcite  is  thinly  coated  with  quartz,  to  the 
last,  in  which  it  is  all  quartz.  Such  crystals  are  pseudoinorphs 
of  quartz  after  calcite.  Siliceous  fossil  shells  and  corals  are 
similar  pseudomorphs  after  catcite,  since  shells  and  corals  con- 
sist chiefly  of  calcite.  Other  quartz  pseudomorphs  have  the 
form  of  fluorite,  barite,  etc. 

Again,  the  forms  of  calcite  occur  with  the  constitution  of 
limonite,  a  hydrous  iron  oxide.  In  such  a  case  the  iron  oxide 
was  in  the  solution  that  corroded  and  dissolved  away  the 
calcite. 

Again,  the  forms  of  calcite  occur  with  the  constitution  of 
serpentine,  a  hydrous  magnesium  silicate  ;  and  in  this  ctiso  the 
ingredients  of  the  serpentine  silicate  were  present  when  the 


62  CRYSTALLOGRAPHY. 

calcite  was  dissolved  away  by  the  corrosive  solvent,  and  took 
its  place  as  the  calcite  particles  were  removed. 

In  all  the  above  cases  the  pseudomorphs  were  made  by  simple 
removal  and  cotemporaneous  substitution. 

Again,  crystals  of  the  form  of  chrysolite,  a  magnesium  sili 
ca^.e,  occur,  altered  to  serpentine,  a  hydrous  magnesium  silicate. 
II  3re  the  pseudomorph  was  made  by  a  process  of  alteration, 
part  of  the  ingredients  remaining,  and  only  water  added. 

Again,  crystals  of  siderite  (spathic  iron  or  iron  carbonate) 
occur  changed  to  limoriite,  a  hydrous  iron  oxide.  Here  there 
was  an  oxidation  of  the  iron  of  the  carbonate,  and  the  addition 
of  water.  This  is  another  example  of  pseudomorphs  by  altera- 
tion. Similarly  orthoclase  changes  to  kaolin,  and  kaolin  has 
the  form  at  times  of  orthoclase  crystals. 

Again,  crystals  of  the  form  of  those  of  common  salt  occur 
consisting  of  clay  or  of  calcite,  which  were  made  by  deposition 
in  a  cavity  left  by  the  dissolving  away  of  an  imbedded  crystal 
of  salt.  These  are  pseudomorphs  by  deposition. 

Again,  crystals  of  aragonite,  prismatic  calcium  carbonate, 
occur  consisting  of  calcite  or  rhombohedral  calcium  carbon- 
ate ;  and  here  there  is  a  change  in  crystallization  without  any 
change  of  chemical  composition. 

7.  Fracture. — Kinds  of  fracture  in  these  crystalline  aggre- 
gates depend  on  the  size  and  form  of  the  particles,  their  cohe- 
sion, and  to  some  extent  their  having  cleavage  or  not. 

Among  granular  varieties,  the  influence  of  cleavage  is  in  all 
cases  very  small,  and  in  the  finest  almost  or  quite  nothing.  The 
term  hackly  is  used  for  the  surface  of  fracture  of  a  metal,  when 
the  grains  are  coarse,  hard,  and'  cleavable,  so  as  to  be  sharp 
and  jagged  to  the  touch  ;  even,  for  any  surface  of  fracture  when 
it  is  nearly  or  quite  flat,  or  not  at  all  conchoidal ;  conchoidal, 
when  the  mineral,  owing  to  its  extremely  fine  or  cryptocrystal- 
line  texture  and  hardness,  breaks  with  shallow  concavities  and 
convexities  over  the  surface,  as  in  the  case  of  flint.  The  word 
conchoidal  is  from  the  Latin  concha,  a  shell.  These  kinds  of 
fracture  are  not  of  much  importance  in  mineralogy,  siuce  they 
distinguish  varieties  of  minerals  only,  and  not  species. 


HAKDNESS — TENACITY — SPECIFIC   GRAVITY.  03 


2.  PHYSICAL  PROPERTIES   OF 
MINERALS. 

THE  physical  properties  referred  co  in  the  description  and 
determination  of  minerals  are  here  treated  under  the  following 
heads:  (1)  Hardness;  (2)  Tenacity;  (3)  Specific  Gravity; 
(4)  Refraction,  Polarization  ;  (5)  Diaphaneity,  Color,  Lustre; 
(6)  Electricity  and  Magnetism  ;  (7)  Taste  and  Odor, 

1.  HARDNE&S. 

The  comparative  hardness  of  minerals  is  easily  ascertained, 
and  should  be  the  first  character  attended  to  by  the  student  in 
examining  a  specimen.  It  is  only  necessary  to  draw  a  lile 
across  the  specimen,  or  to  make  trials  of  scratching  one  wi.th 
another.  As  standards  of  comparison  the  following  minerals 
have  been  selected,  increasing  gradually  in  hardness  from  talc, 
which  is  very  soft  and  easily  cut  with  a  knife,  to  the  diamond. 
This  table,  called  the  scale  of  hardness,  is  as  follows  : 

1,  talc,  common  foliated  variety;  2,  rock  salt  j  3,  calcfct 
transparent  variety  ;  4,  Jluorite,  crystallized  variety;  5,  apatite, 
transparent  crystal ;  6,  ort/ioclase,  cleavable  variety  ;  7,  quartz, 
transparent  variety  ;  8,  topaz,  transparent  crystal ;  9,  sapphire^ 
cleavable  variety;  10,  diamond. 

If,  on  drawing  a  file  across  a  mineral,  it  is  impressed  as  easily 
as  Jluorite,  the  hardness  is  said  to  be  4 ;  if  as  easily  as  ortho- 
close,  the  hardness  is  said  to  be  6  ;  if  more  easily  than  ortho- 
clase,  but  with  more  difficulty  than  apatite,  its  hardness  is  de- 
scribed as  5J  or  5 '5. 

The  file  should  be  run  across  the  mineral  three  or  four  times, 
and  care  should  be  taken  to  make  the  trial  on  angles  equally 
blunt,  and  on  parts  of  the  specimen  not  altered  by  exposure. 
Trials  should  also  be  made  by  scratching  the  specimen  under 
examination  with  the  minerals  in  the  above  scale,  since  some- 
times, owing  to  a  loose  aggregation  of  particles,  the  file  wears 
tlown  the  specimen  rapidly,  although  the  particles  are  very 
haru. 

In  crystals  the  hardness  is  sometimes  appreciably  different  in 
degree  in  the  direction  of  different  axes.  In  crystals  of  mic* 


64  PHYSICAL    PROPERTIES    OF   MINERALS 

the  hardness  is  less  on  the  basal  plane  of  the  prism,  that  is,  on 
the  cleavage  surface,  than  it  is  on  the  sides  of  the  prism.  On 
the  contrary,  the  terminatitn  of  a  crystal  of  cyanite  is  harder 
than  the  lateral  planes  The  degree  of  hardness  in  different 
directions  may  be  obtained  with  great  accuracy  by  means  of  an 
instrument  called  a  sclerometer. 


2.  TENACITY. 

The  following  rather  indefinite  terms  are  used  with  reference 
to  the  qualities  of  tenacity,  malleability,  and  flexibility  in  min- 
erals : 

1.  ^Brittle. — When  a  mineral  breaks  easily,  or  when  parts  of 
the  mineral  separate  in  powder  on  attempting  to  cut  it. 

2.  Malleable. — When  slices  may  be  cut  off,  and  these  slices 
will  flatten  out  under  the  hammer,  as  in  native  gold,  silver, 
copper. 

3.  Sectile. — When  thin  slices  maybe  cut  off  with  a  knife. 
All  malleable  minerals  are  sectile.      Argentite  and  cerargyrite 
are  examples  of  sectile  ores  of  silver.     The  former  cuts  nearly 
like  lead  and  the  latter  nearly  like  wax,  which  it  resembles. 
Minerals  are  imperfectly  sectile  when  the  pieces   cut  off  pul- 
verize easily  under  a  hammer,  or  barely  hold  together,  as  sele- 
nite. 

4.  Flexible.  — When  the  mineral  will  bend,  and  remain  bent 
after  the  bending  force  is  removed.      Example,  talc. 

5.  Elastic. — When,  after  being  bent,  it  will  spring  back  to 
its  original  position.      Example,  mica. 

A  liquid  is  said  to  be  viscous  when  on  pouring  it  the  drops 
lengthen  and  appear  ropy.  Example,  petroleum. 


3.  SPECIFIC  GRAVITY. 

The  specific  gravity  of  a  mineral  is  its  weight  compared  with 
that  of  some  substance  taken  as  a  standard.  For  solids  ar.d 
liquids  distilled  water,  at  60°  F.,  is  the  standard  ordinarily 
used  ;  and  if  a  mineral  weighs  twice  as  much  as  water,  its  spe- 
cific gravity  is  "2  ;  if  three  times  it  is  three.  It  is  then  necessary 
to  compare  the  weight  of  the  mineral  with  the  weight  of  an 
equal  bulk  of  water.  The  process  is  as  follows  : 

First  weigh  a  fragment  of  the  mineral  in  the  ordinary  way, 


SPECIFIC   GRAVITY. 


65 


with  a  delicate  balance  j  next  suspend  the  mineral  by  a  hair,  or 
fibre  of  silk,  or  a  fine  platinum  wire,  to  one  of  the  scales,  im- 
merse it  thus  suspended  in  a  glass  of  distilled  water  (keeping 
the  scales  clear  of  the  water)  and  weigh  it  again;  subtract  the 
second  weight  from  the  first,  to  ascertain  the  loss  by  immersion, 
and  divide  the  first  by  the  difference  obtained  ;  the  result  is  the 
specific  gravity.  The  loss  by  immersion  is  equal  to  the  weight 
of  an  equal  volume  of  water.  The  trial  should  be  made  on  a 
small  fragment ;  two  to  five  grains  are  best.  The  specimen 
should  be  free  from  impurities  and  from  pores  or  air-bubbles. 
For  exact  results  the  temperature  of  the  water  should  be  noted, 
and  an  allowance  be  made  for  any  variation  from  the  height  of 
thirty  iuches  in  the  barometer.  The  observation  is  usually 
made  with  the  water  at  a  temperature  of  60°  F.  ;  39° '5  F.,  the 
temperature  of  the  maximum  density  of  water,  is  preferable. 

The  accompanying  figure  represents  the 
spiral  balance  of  Jolly,  by  which  the  weight 
is  measured  by  the  torsion  of  a  spiral  brass 
wire.  On  the  side  of  the  upright  (A)  which 
faces  the  spiral  wire,  there  is  a  graduated 
mirror,  and  the  readings  which  give  the 
weight  of  the  mineral  in  and  out  of  water  are 
made  by  means  of  an  index  (at  m)  connected 
with  the  spiral  wire ;  and  its  exact  height, 
with  reference  to  the  graduation,  is  obtained 
by  noting  the  coincidence  between  it  and 
i:s  image  as  reflected  by  the  graduated  mir- 
ror, c  and  d  are  the  pans  in  which  the  piece 
of  mineral  is  placed,  first  in  c,  the  one  out 
of  the  water,  and  then  in  d,  that  in  the 
water. 

Another  process,  and  one  available  for 
vorous  as  well  as  compact  minerals,  is  per- 
.ormed  with  a  light  glass  bottle,  capable  of 
holding  exactly  a  thousand  grains  (or  any 
known  weight)  of  distilled  water.  The 
specimen  should  be  reduced  to  a  coarse  pow- 
der, Pour  out  a  few  drops  of  water  from 
the  bottle  and  weigh  it ;  then  add  the  pow- 
dered mineral  till  the  water  is  again  to  the  brim,  and  reweigh 
it ;  the  difference  in  the  two  weights,  divided  by  the  loss  oi 
water  poured  out,  is  the  specific  gravity  sought.  The  weight 
of  the  glass  bottle  itself  is  here  supposed  to  be  balanced  by  an 
squivalent  weight  in  the  other  scale. 
5 


771 


66  PHYSICAL   PROPERTIES   OF   MINERALS. 


4.  REFRACTION  AND  POLARIZATION. 

Minerals  differ  widely  in  their  refracting  and  polarizing 
properties,  and  hence  these  properties  are  a  convenient  means 
of  distinguishing  species.  The  explanations  of  the  subject,  and 
the  methods  of  careful  experimenting,  will  be  found  in  treatises 
on  optics,  and  also  at  considerable  length,  and  with  minute 
directions  as  to  the  use  of  instruments,  in  the  Text-Book  of 
Mineralogy.  Only  a  few  of  the  simpler  facts  required  for  the 
ordinary  purposes  of  the  mineralogist  are  here  mentioned. 

The  character  of  the  refraction  varies  according  to  the  sys- 
tem of  crystallization. 

A.  In  isometric  crystals  there  is  simple  refraction  alike  in 
all  directions,  and  no  polarization. 

B=  In  dimetric  and  hexagonal  crystals  the  vertical  axis,  or 
axis  of  symmetry,  is  the  direction  of  the  optic  axis  ;  in  all 
directions  except  this  a  transmitted  ray  of  light  is  doubly  re- 
fracted. Such  crystals  are  optically  uniaxial. 

C.  In  trimetric,  monoclinic,  and  triclinic  crystals,  which 
have  the  three  axes  unequal,  there  are  two  directions  of  no 
double-refraction.  Such  crystals  are  optically  biaxial. 

1.  Isometric  System. — In  the  isometric  system  there  is  no 
reference  whatever  in  the  refraction  to  crystalline  structure, 
and  in  this  respect  substances  thus  crystallizing  are  like  water. 
There  is  only  simple  refraction.     The  index  of  refraction  is  ob- 
tained by  dividing  the  sine  of  the  angle  of  incidence  of  a  ray  of 
light  by  the  sine  of  its  angle  of  refraction.     Thus  if  a  ray  of 
light  strike  the  surface  of  a  transparent  plate  of  the  mineral  at 
an  angle  of  40°  from  the  perpendicular,  and  then  passes  through 
the  plate  at  an  angle  of  30°  from  the  perpendicular,  owing  to 
the  refraction,  the  sine  of  40°  divided  by  the  sine  of  30°  will 
be  the  index  of  refraction.     Now  the  index  of  refraction  of  air 
being  made  the  unit,  that  of  water  is  1  '335  ;  of  fluorite,  1'434  ; 
of  rock  salt,    1-557;  of  spinel,    1*764;    of  garnet,    1-815;    of 
blende,  2-260;  of  diamond,  2'439. 

2.  Crystals  Uniaxial  in  Polarization. — A  transparent  cleav- 
age plate  from  a  crystal  of  calcite  shows  what  is  called  double 
refraction.     Placed  over  a  line  drawn  on  any  surface,  two 
parallel  lines  are  seen,  one  produced  by  the  ordinary  ray,  and 
the  other  by  the  extraordinary  ray.     Both  rays  are  polarized, 
and  in  planes  at  right  angles  to  each  other.     Prisms,  called 
Nicol  prisms,  made  from  transparent  calcite  (Iceland  Spar), 
are   employed  for   obtaining   polarized   light.     Transparent 


REFRACTION    AND    POLARIZATION. 


67 


plates  of  tourmaline,  cut  from  a  crystal  parallel  to  the  vertical 
axis,  also  are  used  for  this  purpose.  Another  method  of  ob- 
taining it  is  by  reflection — light,  when  reflected  at  a  certain 
angle  from  a  polished  surface,  being  polarized ;  the  angle  of 
reflection  differs  for  different  substances. 


The  above  figure  represents  a  simple  polariscope  made  with 
two  tourmaline  plates,  which  is  convenient  for  many  ordinary 
observations.  The  best  instruments  for  the  purpose  are  made 
with  Nicol  prisms,  and  are  adapted  to  microscopic  work.  The 
prisms,  placed  within  the  tube  of  the  instrument,  one  of  them 
below  the  stage,  are  arranged  so  as  to  admit  of  revolution ;  and 
the  stage  also  has  a  graduated  circle  and  revolves.  The  com- 
pound microscope  also  is  often  converted  into  a  polariscope  by 
Nicol  prisms  arranged  for  this  purpose. 

When  a  crystal  with  one  axis  of  polarization,  as,  for  example, 
calcite,  is  examined  by  means  of  a  ray  of  polarized  light  passed  in 
the  direction  of  the  vertical  axis,  concentric  circular  rings  are 
seen,  having  the  colors  of  the  spectrum  intersected  by  either  a 
black  or  a  white  cross,  as  in  figs.  1,  2.  To  make  the  observa- 

3. 


tion  it  is  necessary  that  the  calcite  crystal  should  have  its  ex- 
tremities polished  at  right  angles  to  the  vertical  axis.  If  a 
tourmaline  plate  be  placed  against  or  near  one  of  its  polished 


68  PHYSICAL    PROPERTIES    OF   MINERALS. 

faces,  and  a  similar  tourmaline  plate  in  front  of  the  opposite 
face,  the  colored  rings  will  be  seen  on  looking  through  ;  and  by 
revolving  one  of  the  tourmaline  plates  a  change  will  be  observed 
at  each  90°  of  revolution,  in  the  colors  of  the  rings,  and  in  the 
variations  in  appearance  of  the  cross  from  black  to  white,  and 
the  reverse.  The  fact  in  any  case  that  the  rings  of  color  are 
perfect  circles,  and  the  black  cross  a  symmetrical  one,  is  proof 
that  the  crystal  is  either  of  the  dimetric  or  hexagonal  system. 
But  sometimes  very  exact  observation  is  necessary  to  deter- 
mine the  truth. 

3.  Crystals  Biaxial  in  Polarization. — Biaxial  crystals  are 
those  having  two  optic  axes,  and  the  angle  between  them  is 
called  the  axial  angle. 

When  a  section  of  such  a  crystal,  at  right  angles  to  the  line 
bisecting  the  acute  axial  angle,  is  viewed  in  converging  polar- 
ized light,  the  two  axes  are  seen  with  a  series  of  elliptical  col- 
ored rings  surrounding  each.  If  the  section  is  so  placed  that 
the  line  joining  the  axes  coincides  with  the  vibration-plane  of 
either  Nicol  prism,  or  tourmaline  plate,  an  unsymmetrical 


0. 


GLAUBER   SALT.  PHLOGOPITE,    ANTWERP,  N.  Y. 

black  cross  is  also  seen,  as  in  fig.  4;  if  it  makes  an  angle  of  45° 
with  this,  two  curved  black  bars  are  observed,  as  in  fig.  5.  In 
either  case  the  colors  are  reversed,  and  the  black  changed  to 
white  as  one  of  the  Nicols  is  revolved.  Fig.  6  shows  the 
axial  figure  for  phlogopite  (in  the  second  position  mentioned 
above)  where  the  axial  angle  is  very  small.  The  rings  are  loss 
numerous  and  farther  apart  the  thinner  the  section  that  is 
employed  in  making  the  observations. 

In  muscovite  (common  mica)  the  angle  between  the  axes  is 
50°  to  70°,  and,  if  the  tourmaline  tongs  are  employed,  the  two 


REFRACTION    AND    POLARIZATION.  C9 

series  of  rings  are  visible  only  when  viewed  in  directions  very 
oblique  to  one  another. 

4.  Circular  Polarization  in  Uniaxial  Crystals. — It  is  stated 
on  page  53  that  quartz  crystals  have  often  a  left  handed  and  a 
right-handed  arrangement  of  planes.     This  is  connected  with  a 
right-handed  and  left-handed  molecular  structure  in  crystals  of 
this  species.     When  a  plate  cut  at  right  angles  to  the  axis  is  ex- 
amined by  the  polarized  light,  instead  of  presenting  a  black 
cross,  the  centre  of  the  rings  appears  brightly  colored,  and  if  the 
polarizer   is  revolved,  this  color  changes  from  blue  to  yellow, 
thnn  red,   right-handed    crystals  requiring   revolution    to    the 
right  and  left-handed  to  the  left  for  this  succession.     This  prop- 
erty seems  to  distinguish  the  smallest  grains  of  quartz,  and  may 
be  easily  observed  in  a  good  polariscope. 

5.  Anomalies  in  Polarization. — There   are    some    isometric 
crystals  which  have  the  property  of  polarization.     Boracite  is 
one  example ;  and  it  is  explained  by  the  presence  of  another 
mineral  in  minute  particles,  distributed  regularly  through  the 
crystals.      Perofskite  is  another  case ;  and  it  has  suggested  a 
doubt  as  to  its  being  isometric.      Octahedrons  of  alum  some- 
times have   polarization,  and  it  has 

been  shown  to  be  due  to  the  crystals 
being  made  up  of  thin  plates — light, 
when  transmitted  through  a  pile  of 
such  plates,  becoming  polarized.  Dia- 
monds are  sometimes  vmiaxial. 

Aualcite  was  long  since  described 
by  Sir  David  Brewster  as  an  example 
of  polarization  under  the  isometric 
system.  Its  trapezohedrons  exhibit 
a  symmetrical  arrangement  of  lines  of 
prismatic  colors  and  alternating  dark 
lines  with  cross-bands,  as  imperfectly 
shown  in  the  annexed  figure.  Trapezohedrons  of  leucite  are 
somewhat  similar  in  their  polarizing  character.  The  effect  in 
both  species  is  connected  with  twinning ;  but,  besides,  accord- 
ing to  recent  observers,  the  crystallization  is  dimelric.  One 
writer  makes  crystals  of  analcite  to  be  trimetric  twins,  analogous 
those  of  phillipsite.  Twinning  in  crystals  is  a  very  common 
source  of  irregularities.  A  regular  twinning  of  laminae  of  bi- 
axial crystals  around  a  centre  may  give  a  uniaxial  character  to 
the  twin.  Apophyllite  is  a  dimetric  species,  showing  peculiari- 
ties in  its  colors  arising  from  the  different  action  of  the  mineral 
in  light  of  different  colors. 


70  PHYSICAL  PROPERTIES   OF  MENEBAL8. 

5.  DIAPHANEITY,  LUSTRE,  COLOR. 
1.  DIAPHANEITY. 

Diaphaneity  is  the  property  which  many  objects  possess  of 
transmitting  light ;  or,  in  other  words,  of  permitting  more  or 
less  light  to  pass  through  them.  This  property  is  often  called 
transparency,  but  transparency  is  properly  one  of  the  degrees 
cf  diaphaneity.  The  following  terms  are  used  to  express  the 
different  degrees  of  this  property  : 

Transparent — a  mineral  is  said  to  be  transparent  when  the 
outlines  of  objects,  viewed  through  it,  are  distinct.  Example, 
glass,  crystals  of  quartz. 

Subtransparent;  or  semitransparent — when  objects  are  seen 
but  their  outlines  are  indistinct. 

Translucent — when  light  is  transmitted,  but  objects  are  not 
seen.  Loaf  sugar  is  a  good  example  j  also  Carrara  marble. 

Subtranslucent — when  merely  the  edges  transmit  light  faintly. 

When  no  light  is  transmitted  the  mineral  is  described  as 
opaque. 

2.  LUSTRE. 

The  lustre  of  minerals  depends  on  the  nature  of  their  surfaces, 
which  causes  more  or  less  light  to  be  reflected.  There  are  dif- 
ferent degrees  of  intensity  of  lustre,  and  also  different  kinds  of 
lustre. 

a.  The  kinds  of  lustre  are  six,  and  are  named  from  some 
familiar  object  or  class  of  objects. 

1.  Metallic — the  usual  lustre  of  metals.     Imperfect  metallic 
lustre  is  expressed  by  the  term  submetallic. 

2.  Vitreous — the    lustre   of  broken    glass.       An    imperfect 
vitreous  lustre  is  termed  subvitreous.     Both  the  vitreous  and 
sub  vitreous  lustres  are  common.      Quartz  possesses  the  former 
in  an  eminent  degree  ;  calcareous  spar  often  the  latter.      This 
kind  of  lustre  may  be  exhibited  by  minerals  of  any  color. 

3.  Hesinous — lustre  of  the   yellow  resins.     Example,  some 
opal,  zinc  blende. 

4.  Pearly — like  pearl.     Example,  talc,  native  magnesia,  gtil- 
bite,  etc.      When   united   with    submetallic    lustre    the   term 
metallic-pearly  is  applied. 

ii.   8Uky — like  silk;  it  is  the  result  of  a.  fibrous  structure. 


DIAPHANEITY— LU8TKE COLOK.  71 

Example,  fibrous  calcite,  fibrous  gypsum,  and  many  fibrous 
minerals,  more  especially  those  which  in  other  forms  have  a 
pearly  luwtre. 

6.  Adamantine — the  lustre  of  the  diamond.  When  sub- 
metallic,  it  is  termed  metallic  adamantine.  Example,  some 
varieties  of  white  lead  ore  or  cerussite. 

b.  The  degrees  of  intensity  are  denominated  as  follows: 

1.  Splendent — when  the  surface  reflects  light  with  great  bril- 
liancy and  gives  well-defined  images.     Example,  Elba  hematite, 
tin  ore,  some  specimens  of  quartz  and  pyrite. 

2.  Shining — when  an  image  is  produced,  but  not  a  well-de- 
fined image.     Example,  calcite,  celestite. 

3.  Glistening — when  there  is  a  general  reflection  from  the 
surface,  but  no  image.     Example,  talc. 

4.  Glimmering — when  the  reflection  is  very  imperfect,  and 
apparently  from  points  scattered  over  the  surface.     Example, 
flint,  chalcedony. 

A  mineral  is  said  to  be  dull  when  there  is  a  total  absence  of 
lustre.  Example,  chalk. 

3.  COLOR. 

1.  Kinds  of  Color. — In  distinguishing  minerals,  both  the  ex 
ternal  color  and  the  color  of  a  surface  that  has  been  rubbed  01 
scratched,  are  observed.  The  latter  is  called  the  'streak,  and  the 
powder  abraded,  the  streak-powder. 

The  colors  are  either  metallic  or  unmetallic. 

The  metallic  a^  named  after  some  familiar  metal,  as  copper- 
red,  bronze-yeilow,  brass-yellow,  gold-yellow,  steel-gray,  lead- 
gray,  iron-gray. 

The  unmetallic  colors  used  in  characterizing  minerals  are 
various  shades  of  white,  gray,  black,  blue,  green,  yellow,  red  and 
brown. 

There  are  thus  snow-white,  reddish-white,  greenish-white, 
milk-white,  yellowish-white. 

Bluish-gray,  smoke-gray,  greenish-gray,  pearl-gray,  ash-gray. 

Velvet-black,  greenish-black,  bluish-black,  grayish-black. 

Azure-blue,  violet-blue,  sky-blue,  indigo-blue. 

Emerald-green,  olive-green,  oil-green,  grass-green,  apple-green, 
bUckish-green,  pistachio-green  (yellowish). 

Sulphur-yellow,  straw-yellow,  wax-yellow,  ochre-yellow, 
honey-yellow,  orange-yellow. 

Scarlet-red,  blood-red,  flesh  red,  brick-red,  hyaiinth-red,  rose- 
red,  cherry-red. 


72  PHYSICAL    PROPERTIES    OF    MINERALS. 

Hair-brown,  reddish-brown,  chestnut-brown,  yellowish-brown, 
pinchbeck-brown,  wood-brown. 

A  play  of  colors — this  expression  is  used  when  several  pris- 
maiic  colors  appear  in  rapid  succession  on  turning  the  mineral. 
The  diamond  is  a  striking  example  ;  also  precious  opal. 

Change  of  colors — when  the  colors  change  slowly  on  turning 
in  different  positions,  as  in  labradorite. 

Opalescence — when  there  is  a  milky  or  penrly  reflection 
from  the  interior  of  a  specimen,  as  in  some  opals,  and  in  cat's 
eye. 

Iridescence — when  prismatic  colors  are  seen  within  a  crystal, 
it  is  the  effect  of  fracture,  and  is  common  in  quartz. 

Tarnish — when  the  surface  colors  differ  from  the  interior ; 
it  is  the  result  of  exposure.  The  tarnish  is  described  as  irised 
when  it  has  the  hues  of  the  rainbow. 

2.  Dichroism,  Trichroism. — Some  crystals,  under  each  of  the 
systems  excepting  the  isometric,  have  the  property  of  present- 
ing different  colors  by  transmitted  light  in  different  directions. 
The  property  is  called  dichroism  when  these  colors  are  seen  in 
two  directions,  and  trichroism  (or  pleochroism)  if  seen  in  three 
directions.  The  colors  are  always  the  same  in  the  direction 
of  equal  axes  and  often  unlike  in  the  direction  of-  unequal 
axes.  As  dimetric  and  hexagonal  crystals  have  the  lateral  axes 
equal  they  can  present  different  colors  only  in  two  directions, 
the  vertical  and  lateral;  while  all  crystals  that  are  optically 
biaxial  may  be  trichroic. 

The  mineral  iolite  is  a  noted  example,  and  received  the  name 
dichroite  on  account  of  this  property.  Transparent  colored 
crystals  of  tourmaline,  topaz,  epidote,  mica,  diaspore,  and  many 
other  species  exhibit  it.  Tourmaline  crystals,  when  transpar- 
ent or  translucent  transverse  to  the  prism,  are  opaque  in  the 
direction  of  the  vertical  axis  ;  and  so  also  are  thick  crystals  of 
mica.  Colored  varieties  of  hornblende  are  dichroic,  while 
those  of  the  related  mineral,  pyroxene,  are  not  so. 

This  quality  is  best  observed  by  means  of  polarized  light.  On 
examining  a  mineral  with  a  tourmaline  plate,  or  Nicol  prism,  the 
two  colors  in  a  dichroic  mineral  are  successively  seen  as  the 
tourmaline  or  Nicol  is  revolved  ;  and  if  there  is  no  dichroism 
there  is  no  change  of  color.  A  small  instrument,  containing  a 
prism  of  calcite,  has  been  constructed  for  showing  the  dichro- 
ism, called  the  dichroscope.  On  looking  through  it  at  a  di- 
chroic crystal,  the  aperture  against  the  crystal  appears  double, 
owing  to  the  double  refraction  of  the  calcite,  one  image  being 
made  by  the  ordinary  ray  and  the  other  by  the  extraordinary 


ELECTBICITY   AND   MAGNETISM.  73 

ray ;  and  the  two  colors  are  seen  side  by  side,  at  intervals  of 
90°  in  the  revolution  of  the  mineral. 

For  opaque  minerals  it  is  necessary  to  make  a  thin  transparent 
section  of  the  mineral  and  examine  it  with  a  polari  scope,  or  with 
a  microscope  arrange^  ''.  ict  as  one  by  the  addition  of  one  Nicol 
prism.  The  opaque  /-nblende  of  rocks  is  thus  distinguished 
from  pyroxene,  and  so  in  other  cases. 

3.  Asterism. — Some  crystals,  especially  the  hexagonal,  when 
viewed  in  the  direction  of  the  vertical  axis,  present  peculiar  re- 
flections in  six  radial  directions.     This  arises  either 'from  pecu- 
liarities of  texture  along  the  axial  portions,  or  from  some  im- 
purities.    A  remarkable  example  of  it  is  that  of  the  asteriated 
sapphire,  and  the  quality  adds   much  to  its  value  as  a  gem. 
The  six  rays  are  sometimes  alternately  shorter,  indicating  the 
rhombohedral  character  of  the  crystal. 

4.  Phosphorescence. — Several  minerals  give  out  light  either 
by  friction  or  when  gently  heated.     This  property  of  emitting 
light  is  called  phosphorescence. 

Two  pieces  of  white  sugar  struck  against  one  another  give  a 
feeble  light,  which  may  be  seen  in  a  dark  place.  The  same 
effect  is  obtained  on  striking  together  fragments  of  quartz,  and 
even  the  passing  of  a  feather  rapidly  over  some  specimens  or 
zinc  blende  is  sufficient  to  elicit  light. 

Fluorite  is  the  most  convenient  mineral  for  showing  phos 
phorescence  by  heat.  On  powdering  it,  and  throwing  it  on  a 
plate  of  metal  heated  nearly  to  redness,  the  whole  takes  on  a 
bright  glow.  In  some  varieties  the  light  is  emerald  green ;  in 
others,  purple,  rose,  or  orange.  A  massive  fluor,  from  Hun 
tington,  Connecticut,  shows  beautifully  the  emerald  green  phos- 
phorescence. 

Some  kinds  of  white  marble,  treated  in  the  same  way,  gU  ^ 
out  a  bright  yellow  light. 

After  being  heated  for  a  while  the  mineral  loses  its  phoa- 
phorescence ;  but  a  few  electric  shocks  will,  in  many  cases,  to 
some  degree  restore  it  again. 


6.  ELECTRICITY,  AND  MAGNETISM. 

ELECTRICITY. — Many  minerals  become  electrified  on  being 
nibbed,  so  that  they  will  attract  cotton  and  other  light  sub- 
stances ;  and  when  electrified  some  exhibit  positive  and  others 
negative  electricity,  when  brought  near  a  delicately  suspended 
magnetic  needle.  The  diamond,  whether  polished  or  not,  ai- 


74  PHYSICAL   PROPERTIES    OF   MINERALS. 

ways  exhibits  positive  electricity,  while  other  gems  become 
negatively  electric  in  the  rough  state,  and  positively  only  in  the 
polished  state.  Some  minerals,  thus  electrified,  retain  the  powoi 
of  electric  attraction  for  many  hours,  as  topaz,  while  others  lose 
it  in  a  few  minutes. 

Many  minerals  become  electric  when  heated,  and  such  speciea 
are  said  to  be  pyro~electric,  from  the  Greek  put,  fire,  and 
electric. 

A  prism  of  tourmaline,  on  being  heated,  becomes  polar  ;  ono 
extremity  will  be  attracted,  the  other  repelled,  by  a  pole  of  a 
strong  magnet.  The  prisms  of  tourmaline  have  different  second- 
ary planes  at  the  two  extremities. 

Several  other  minerals  have  this  peculiar  electric  property, 
especially  boracite  and  topaz,  which,  like  tourmaline,  are  hemi- 
hedral  in  their  modifications.  Boracite  crystallizes  in  cubes, 
with  only  the  alternate  solid  angles  similarly  replaced  (figs.  39, 
40,  page  25).  Each  solid  angle,  on  heating  the  crystals,  be- 
comes an  electric  pole ;  the  angles  diagonally  opposite  are  dif- 
ferently modified  and  have  opposite  polarity.  Pyroelectricity 
has  been  observed  also  in  crystals  that  are  not  hemihedral,  and 
in  many  mineral  species.  In  some  cases  the  number  of  poles  is 
more  than  two.  In  prelmite  crystals  a  large  series  occur  dis- 
tributed over  the  surface. 

MAGNETISM. — The  name  Lodestone  is  given  to  those  specimens 
of  an  ore  of  iron,  called  magnetite  which  have  the  power  of  at- 
traction like  a  magnet ;  it  is  common  in  many  beds  of  magnetite. 
When  mounted  like  a  horse-shoe  magnet,  a  good  lodestone  will 
lift  a  weight  of  many  pounds.  This  is  the  only  mineral  that 
has  decided  magnetic  attraction.  But  several  ores  containing 
iron  are  attracted  by  the  magnet,  or,  when  brought  near  a 
magnetic  needle,  will  cause  it  to  vibrate;  and  moreover,  the 
metals  nickel,  cobalt,  manganese,  palladium,  platinum  and  os- 
mium, have  been  found  to  be  slightly  magnetic. 

Many  minerals  become  attractable  by  the  magnet  after  being 
heated  that  are  not  so  before  heating.  This  arises  from  a 
change  of  part  or  all  of  the  iron  to  the  magnetic  oxide. 


7.  TASTE  AND  ODOR. 

Taste  belongs  only  to  the  soluble  minerals ;  the  kinds  are— 

1.  Astringent — the  taste  of  vitriol. 

2.  Sweetish-astringent — the  taste  of  alum. 

3.  Saline — taste  of  common  salt. 


TASTE    AND   ODOB.  75 

4.  Alkaline — taste  of  soda. 

5.  Cooling — taste  of  saltpetre. 

6.  Bitter — taste  of  epsom  salts. 

7.  Sour — taste  of  sulphuric  acid. 

Odor  is  not  given  off  by  minerals  in  the  «ry,  unchanged 
state,  except  in  the  case  of  a  few  gases  and  soluble  minerals. 
By  friction,  moistening  with  the  breath,  the  action  of  acids  and 
the  blowpipe,  odors  are  sometimes  obtained,  which  are  thus 
designated : 

1.  Alliaceous — the  odor  of  garlic.     It  is  the  odor  of  burning 
arsenic,  and   is  obtained  by  friction,  and    more   distinctly  by 
means  of  the  blowpipe,  from  several  arsenical  ores. 

2.  Horse-radish  odor — the  odor  of  decaying  horse-radish.    It 
is  the  odor  of  burning  selenium,  and  is  strongly  perceived  when 
ores  of  this  metal  are  heated  before  the  blowpipe. 

3.  Sulphureous — odor  of    burning    sulphur.     Friction    will 
elicit  this  odor  from  pyrites,  and  heat  from  many  sulphides. 

4.  Fetid — the  odor  of  rotten  eggs  or  sulphuretted  hydrogen. 
It  is  elicited  by  friction  from  some  varieties  of  quartz  and  lime- 
stone. 

5.  Argillaceous — the  odor  of  moistened  clay.     It  is  giren  oflf 
by  serpentine  and  some  allied  minerals  when  breathed  upon. 
Othf  r?,  as  pyrargillite,  afford  it  when  heated. 


70 


CHEMICAL   PROPERTIES   OF  MINERALS. 


8.   CHEMICAL  PROPERTIES 
MINERALS. 


OP 


THE  chemical  properties  of  minerals  are  of  two  kinds.  (1) 
Those  of  the  chemical  composition  of  minerals,  (2)  those  de- 
pending on  their  chemical  reactions,  with  or  without  fluxes,  in- 
cluding results  obtained  by  means  of  the  blowpipe. 


1.  CHEMICAL  COMPOSITION. 


All  the  elements  made  known  by  chemistry  are  found  in 
minerals,  for  the  mineral  kingdom  is  the  source  of  whatever 
living  beings — plants  and  animals— contain  or  use.  A  list  of 
these  elements,  as  at  present  made  out,  is  contained  in  the  fol- 
lowing table,  together  with  the  symbol  for  each  used  in  stating 
the  composition  of  substances.  These  symbols  are  abbreviations 
of  the  Latin  names  for  the  elements.  A  few  of  these  Latin 
names  differ  much  from  the  English,  as  follows  : 


Stibium  Sb    =  Antimony 

Cuprum  Cu  =  Copper 

Ferrum  Fe   =r  Iron 

Plumbum         Pb   =z  Lead 
Hydrargyrum  Hg  =  Mercury 


Kalium 

Argentum 

Natrium 

Stannura 


K  =  Potassium 

Ag  =  Silver 

Na  =  Sodium 

Sn  =  Tin 


Wolframium      W     =  Tungsten 


TABLE  OF  THE  ELEMENTS. 


Aluminum 

Antimony 

Arsenic 

Barium 

Bismuth 

Boron 

Bromine 

Cadmium 

Ceesium 

Calcium 

Carbon 

Cerium 

Chlorine 

Chromium 

Cobalt 


Al 

27-4 

Sb 

120 

As 

75 

Ba 

137 

Bi 

210 

B 

11 

Br 

80 

Cd 

112 

Cs 

133 

Ca 

40 

C 

12 

Ce 

138 

Cl 

35-5 

Cr 

522 

Co 

58-8 

Columbium  (Niobium)  Cb  (Nb)  94 

Copper  Cu  63 '4 

Didymium  D  144 '8 

Erbium  E  168 -9 

Fluorine  F  19 

Gallium  Ga  68  ? 
Glucinum (Beryllium)  G  (Be)    9 '4 

Gold  Au  197 

Hydrogen  H  1 

Indium  In  113 '4 

Iodine  I  127 

Jridium  Ir  198 

Iron  Fe  56 

Lanthanum  La  139 

Lead  Pb  207 


CHEMICAL   COMPOSITION    OF   MINERALS. 


77 


Li 

7 

Silver 

Mg 

24 

Silicon 

Mn 

55 

Sodium 

Kg 

200 

Strontium 

Mo 

96 

Sulphur 

Ni 

58-8 

Tantalum 

H 

14 

Tellurium 

Oa 

199-2 

Thallium 

0 

16 

Thorium 

Pd 

106-6 

Tin 

P 

31 

Titanium 

Pt 

197-6 

Tungsten 

K 

39-1 

Uranium 

Ro 

104-4 

Vanadium 

Rb 

85-4 

Yttrium 

Ru 

104-4 

Zinc 

8e 

79  '4  '  Zirconium 

Aff 
Si 

108 

28 

Na 

23 

Sr 

87'fl 

S 

32 

Ta 

182 

Te 

128 

Tl 

204 

Th 

235 

Sn 

118 

Ti 

50 

W 

184 

U 

240 

V 

51-2 

Y 

92 

Zn 

65-2 

Zr 

89-6 

Lithium 

Magnesium 

Manganese 

Mercury 

Molybdenum 

Nickel 

Nitrogen 

Osmium 

Oxygen 

Palladium 

Phosphorus 

Platinum 

Potassium 

Rhodium 

Rubidium 

Ruthenium 

Selenium 


The  combining  weights  indicate  the  proportions  in  which  the 
elements  combine.  Thus,  assuming  hydrogen,  the  lightest  of 
the  elements,  to  be  1,  or  the  unit  of  the  series,  the  combining 
weight  of  oxygen  is  16  ;  of  iron,  §6  ;  of  magnesium,  24;  of 
Biilphur,  32;  and  so  on.  When  hydrogen  and  oxygen  combine 
it  is  in  the  ratio  of  2  pounds  of  hydrogen,  or  else  1  pound  of 
hydrogen,  to  16  pounds  of  oxygen,  and  two  different  compounds 
thus  result.  When  oxygen  and  magnesium  combine  it  is  in  the 
ratio  of  16  pounds  of  oxygen  to  24  of  magnesium.  Oxygen  and 
iron  combine  in  the  ratio  of  16  of  oxygen  to  56  of  iron ;  or  of  24 
of  oxygen  (1£  times  16)  to  56.  Sulphur  and  oxygen  combine  in 
the  ratio  of  32  of  oxygen  to  32  of  sulphur;  or  of  48  to  32  of 
sulphur.  The  combining  weights  are  often  called  the  atomic 
weights. 

The  following  is  the  manner  of  using  the  symbols :  For  the 
compound  consisting  of  hydrogen  and  oxygen  in  the  ratio  of  2 
to  16,  the  chemical  symJJ&l  is  H.,O,  meaning  2  of  hydrogen  to  1 
of  oxygen.  (This  compound  is  water.)  For  the  compound  of 
oxygen  and  magnesium  just  referred  to,  the  symbol  is  MgO; 
for  the  two  compounds  of  oxygen  and  iron,  FeO,  protoxide  of 
iron ;  Fe.,O3,  sesquioxide  of  iron,  the  ratio  of  1  to  1^  being  ex- 
pressed by  2  to  3  ;  for  the  two  compounds  of  sulphur  and  oxy- 
gen, SOa  and  SO3. 

Some  of  the  elements  so  closely  resemble  one  another  that 
their  similar  compounds  are  closely  alike  in  crystallization  and 
other  qualities,  and  they  are  therefore  said  to  be  isomorphous. 

This  is  true  of  iron,  magnesium,  calcium,  and  two  or  three 
other  related  elements.  In  one  group  of  compounds  of  these 
bases,  the  carbonates,  the  crystalline  form  for  each  is  rhombohe- 


78  CHEMICAL   PROPERTIES   OF  MINERALS. 

dral,  and  among  them  there  is  a  difference  of  less  than  two  d&. 
grees  in  the  angle  of  the  rhouibohedron.  Besides  a  carbonate 
of  calcium,  a  carbonate  of  magnesium,  and  a  carbonate  of  iron, 
there  is  also  a  carbonate  of  calcium  and  magnesium*  in  which 
half  of  the  calcium  of  the  first  of  these  carbonates  is  replaced 
by  half  an  atom  of  magnesium ;  and  another  species  in  which 
the  base,  instead  of  being  all  magnesium,  is  half  magnesium  and 
half  iron.  By  half  is  here  meant  half  in  the  proportion  of  their 
combining  weights. 

The  replacement  of  one  of  these  elements  by  the  other,  and 
similar  replacements  among  other  groups  of  related  elements, 
run  through  the  whole  range  of  mineral  compounds.  Thus  we 
have  sodium  replacing  potassium,  arsenic  replacing  phosphorus 
and  antimony ',  and  so  on. 

In  the  combinations  of  oxygen  and  iron,  as  illustrated  above, 
oxygen  is  combined  with  the  iron  in  different  proportions. 
FeO  contains  1  of  Fe  (iron)  to  1  of  O  (oxygen)  and  Fe^,  or,  as 
it  is  often  written,  FeO3,  contains  §  Fe  to  1  of  O.  As  the  iron  in 
each  of  these  cases  satisfies  the  oxygen,  it  is  evident  that  the 
iron  must  be  in  two  different  states,  (1)  a  protoxide  state,  and 
(2)  a  sesquioxide  state.  One  part  of  iron  in  this  sesquioxide 
state  ( =  f  Fe)  often  replaces  in  compounds  one  part  of  iron  in 
the  protoxide  state  (or  IFe),  with  no  greater  change  of  quali- 
ties than  happens  in  the  replacement  of  iron  by  magnesium,  or 
calcium,  explained  above ;  or,  avoiding  fractions,  3  parts  of  Fe 
in  the  protoxide  state  replaces  2Fe  in  the  sesquioxide  state. 
Writing  ¥e  for  the  last  2Fe,  the  statement  becomes  1  of  Fe3 
replaces  1  of  Fe.  Aluminium  occurs  only  in  the  sesqui- 
oxide state,  and  the  ordinary  symbol  of  the  oxide  is  A14O8, 
or  AlO3.  But  it  is  closely  related  to  iron  in  the  sesquioxide 
state,  so  that,  using  the  same  mode  of  expression  as  for  iron, 
1  of  Al  replaces  1  of  Fe3,  or  1  of  Mjk,  and  so  on.  Similarly, 
writing  R  for  any  metal,  1  of  R  replaces  1  of  R3.  Again,  in 
potash  (K2O),  soda  (Na2O),  lithia  (Li.,O),  water  (H2O),  one  of 
oxygen  (O)  is  combined  severally  with  2  of  K  (potassium),  of 
Na  (sodium),  of  Li  (lithium),  of  hydrogen ;  And  hence  2K, 
2Na,  2Li,  that  is,  K2,  Na2,  Li2,  may  each  replace  in  compounds 
ICa,  or  IMg,  etc. 

The  elements  potassium,  sodium,  lithium,  hydrogen,  of  which 
it  takes  two  parts  to  combine  with  1  of  oxygen,  are  called 
monads.  Other  elements  of  the  group  of  monads  are  rubidium, 
ccesium,  thallium,  silver,  and  also  fluorine,  chlorine,  bromine, 
iodine.  Still  other  elements  combining  by  two  parts  in  their 
oxygen  or  sulphur  compounds,  etc.,  are  nitrogen,  phosphorus, 


CHEMICAL   COMPOSITION   OF   MINERALS.  79 

intimony,  boron,  columbium,  tantalum,  vanadium,  gold.  For 
example,  for  arsenic  there  are  the  compounds  As2S,  A.8SS3, 
&s2O3,  As,,O5,  etc.  Another  characteristic  of  these  elements  of 
the  hydrogen,  sodium,  chlorine,  and  arsenic  groups  is  that  the 
number  of  equivalents  of  the  acidic  element  in  the  compounds 
into  which  they  enter  is,  with  a  rare  exception,  odd,  and  of  the 
1,  3,  5,  etc.,  series,  and  on  this  account  they  are  called  in 
chemistry  perissads  •  while  the  other  elements,  in  whose  com- 
pounds their  number  is  of  the  1,  2,  3,  etc.  (or  2,  4,  6)  series, 
are  called  artiads.  An  apparent  exception  exists  under  the 
artiads  in  the  sesqui oxides,  but  this  does  not  alter  the  general 
character  of  the  series. 

The  facts  above  cited  sustain  the  general  statement  that 
Ca3,  Mg3,  Mn3,  Zn3,  Fe3,  Al,  Fe,  Mn,  have  equivalent  combin- 
ing values,  and  hence  in  minerals  often  replace  one  another ; 
and  so  also  Ca,  Mg,  Mn,  Zn,  Fe,  K2,  Na2,  Li2,  H2,  may  replace 
one  another.  Similarly,  also,  As2,  or  Sb3  replaces  S  in  some 
minerals. 

With  reference  to  the  classification  of  minerals  the  elements 
may  be  conveniently  divided  into  two  groups:  (1)  the  Acidic, 
and  (2)  the  Basic.  The  former  includes  oxygen  and  the  ele- 
ments which  were  termed  the  acidi/iers  and  acidiftable  elements 
in  the  old  chemistry.  They  are  those  which  have  been  called 
in  mineralogy  the  mineralizing  elements,  since  they  are  the 
elements  which  are  found  combined  with  the  metals  to  make 
them  ores,  that  is,  to  mineralize  them.  The  basic  are  the  rest 
of  the  elements.  The  groups  overlap  somewhat,  but  this  need 
not  be  dwelt  upon  here. 

The  more  important  of  the  acidic  elements  are  the  following : 
oxygen,  fluorine,  chlorine,  bromine,  iodine,  sulphur,  selenium, 
tellurium,  boron,  chromium,  molybdenum,  tungsten,  phosphorus, 
arsenic,  antimony,  vanadium,  nitrogen,  tantalum,  columbium, 
carbon,  silicon. 

Again,  among  the  compounds  of  these  elements  occurring  in 
tho  mineral  kingdom  there  are  two  grand  divisions,  the  binary 
and  the  ternary.  The  binary  consist  of  one  or  more  elements 
of  each  of  the  acidic  and  basic  divisions,  and  the  ternary  of  one 
or  more  elements  of  each  of  these  two  classes,  along  with  oxy- 
gen, fluorine,  or  sulphur  as  a  third.  The  binary  include  the 
sulphides,  arsenides,  chlorides,  fluorides,  oxides,  etc.,  and  tho 
ternary  the  sulphates,  chromates,  borates,  arsenates,  pliospliates^ 
silicates,  carbonates,  etc.,  and  also  the  sulpli-arsenites  and  sulph 
antimonites,  in  which  a  basic  metal  (usually  lead,  copper,  sil- 
ver) is  combined  with  arsenic  or  antimony  and  sulphur. 


80  CHEMICAL   PROPERTIES    OF   MINERALS. 

The  following  are  examples  of  the  symbols  of  binary  imd 
ternary  compounds  : 

1.  Binary. 

1.  Sulphides,  Selenides. — Ag2S  =  silver  sulphide;  Ag2Se  = 
silver  selenide ;  PbS  =  lead  sulphide ;  ZnS  =  zinc  sulphide ; 
FeS2  --—  iron  disulphide. 

2.  Fluorides,  Chlorides,  etc. — CaF2  =  calcium  fluoride  ;  AgCl 
=  silver    chloride ;    AgBr  =  silver   bromide ;     AgT  =  silver 
iodide  ;  Nad  =  sodium  chloride  (common  salt). 

3.  Oxides.  —  A12O3  =  3 ( Al^O)  =  aluminium  sesquioxide  ; 
A  s2O3  =.  arsenic  trioxide  ;  As.;O5  —  arsenic  pentoxide ;  BaO  = 
barium   oxide  ;    B.,O3  =  boron  trioxide  (boracic  acid)  ;  CaO  = 
calcium  oxide   (lime)  ;  CO2  =  carbon  dioxide  (carbonic  acid) ; 
CrO3  =  chromium  trioxide  (chromic  acid) ;  Cu2O  =  copper  sub- 
oxide  ;  CuO  =  copper  oxide  ;  BeO  =  beryllium  oxide  ;  H2O  = 
hydrogen    oxide   (water)  ;     FeO  =  iron    oxide ;    Fe2O3  =  iron 
sesquioxide  ;  PbO  —  lead  oxide  ;  Li2O  =  lithium  oxide  ;  MgO 
=  magnesium  oxide ;    MnO  =  manganese    oxide  ;    Mn2O3  — 
manganese  sesquioxide ;  MnO2  =  manganese  dioxide  ;  P2O5  = 
phosphorus  pentoxide  ;  K2O  —  potassium  oxide  ;  SiO3  =  silicon 
dioxide  (silica) ;  Na2O  =  sodium  oxide  ;  SrO  =  strontium  ox- 
ide ;  SO.,  —  sulphur  dioxide  (sulphurous  acid)  ;  SO3  =  sulphur 
trioxide ;    SnO2  =  tin  dioxide ;    V2O5  =  vanadium  pentoxide 
(vanadic   acid)  ;    WO3  =  tungsten    trioxide    (tungstic   acid)  ; 
ZnO  =  zinc  oxide  ;  ZrO2  —  zirconium  dioxide. 

The  composition  of  these  compounds  may  be  obtained  from 
the  table  of  combining  weights,  page  76.  For  example,  with 
reference  to  the  first  of  them  (AgS),  the  table  gives  for  the 
combining  weight  of  silver  (Ag),  108,  and  for  that  of  sulphur,  32. 
The  elements  exist  in  the  compound  therefore  in  the  proportion 
of  108  to  32,  and  from  it  the  composition  of  a  hundred  parts  ia 
easily  deduced. 

If  the  formula  were  (Ag,  Pb)S,  signifying  a  silver- and- lead 
sulphide,  and  if  the  silver  and  lead  were  in  the  ratio  of  1  to  1, 
than  half  the  combining  weight  of  silver  is  taken;  that  is,  54, 
and  half  the  atomic  weight  of  lead,  which  is  103 -5  ;  and  the 
sum  of  these  numbers,  with  32  for  the  sulphur,  expresses  the 
ratio  of  the  three  ingredients. 

For  A12O3  we  find  the  combining  weight  of  aluminium  27. 4  ; 
doubling  this  for  A12  makes  54*8.  Again,  for  oxygen,  we  find 
16  ;  and  three  times  16  is  48.  54'S  to  48  is  therefore  the  ratio 


CHEMICAL   COMPOSITION   OF   MINERALS.  81 

of  aluminium  to  the  oxygen  in  A.l.jO3,  from  which  the  percent- 
age proportion  may  be  obtained. 


2.    Ternary   Oxygen   Compounds. 

Silicates. — Of  these  compounds  there  are  two  prominent 
groups.  In  one  of  these  groups  the  general  formula  is  RO3Si, 
and  in  the  other  R4  O4  Si.  In  both  of  these  formulas  R  stands 
for  any  basic  elements  in  the  protoxide  state,  as  Ca,  Mg,  Fe, 
etc.,  either  alone  or  in  combination.  In  the  first  of  these  for- 
mulas the  combining  values  of  the  basic  element  R  and  the 
acidic  element  or  silicon,  as  measured  by  their  combinations 
with  oxygen,  are  in  the  proportion  of  1  to  2,  for  R  stands 
for  an  element  in  the  protoxide  state,  while  Si  stands  for  sili- 
con, which  is  in  the  dioxide  state,  its  oxide  being  a  dioxide  • 
and  hence  the  minerals  so  constituted  are  called  Itisilicates.  Ii 
the  second  of  these  formulas  this  ratio  is  2  to  2,  or  1  to  1,  and 
hence  these  are  called  Unisilicates. 

Multiplying  these  formulas  by  3,  they  become  R3O8Si3,  and 
(2R3)  OjoSig ;  and  the  same  composition  is  expressed.  In  this 
form  the  substitution  of  sesquioxide  bases  for  protoxide  may 
be  indicated  :  thus,  RaR  Oia  Si3  signifies  that  half  of  the  2R3  is  re- 
placed by  Al  or  Fe,  or  some  other  element  in  the  sesquioxide 
state. 

There  are  also  some  species  in  which  the  ratio  is  1  to  less 
than  1,  and  these  are  called  Subsilicates. 

The  ratio  here  referred  to  (formerly  known  as  the  oxygen 
ratio)  is  called  the  quantivalent  ratio. 

The  other  ternary  compounds  require  no  special  remarks  in 
this  place. 

2.    CHEMICAL    REACTIONS. 
1.    Trials  in  the  wet  way. 

1.  Test  for  Carbonates. — Into  a  test  tube  put  a  little  hydro- 
chloric acid  diluted  with  one  half  water,  and  add  a  small  por- 
tion in  powder  of  the  mineral.     If  a  carbonate,  there  will  be  a 
brisk  effervescence   caused  by  the  escape  of  carbonic  dioxide 
(carbonic  acid),  when  heat  is  applied,  if  not  before.     With  cal- 
cium carbonate  no  heat  or  pulverization  is  necessary. 

2.  Test  for  Gelatinizing  /Silica. — Some  silicates,  when  pow 

6 


82  CHEMICAL   PROPERTIES   OF   MINERALS. 

tiered  and  treated  with  strong  hydrochloric  acid,  are  decom- 
posed and  deposit  the  silica  in  a  state  of  a  jelly.  The  experi- 
ment may  be  performed  in  a  test  tube,  or  small  glass  flask. 
Sometimes  the  evaporation  of  the  liquid  nearly  to  dryness  is 
necessary  in  order  to  obtain  the  jelly.  Some  silicates  do  not 
afford  the  jelly  unless  they  have  been  previously  ignited  before 
the  blowpipe,  and  some  gelatinizing  silicates  lose  the  power  on 
ignition. 

3.  Decomposability  of  Minerals  by  Acids. — To  ascertain 
whether  a  mineral  is  decomposable  by  acids  or  not,  it  is  very 
finely  powdered  and  then  boiled  with  strong  hydrochloric  acid, 
or,  in  case  of  many  metallic  minerals,  with  nitric  acid.  In 
some  cases  where  no  jelly  is  formed  there  is  a  deposit  of  silica 
in  fine  flakes.  With  the  sulphides  and  nitric  acid  there  is  often 
a  deposit  of  sulphur,  which  usually  floats  upon  the  surface  of 
the  fluid  as  a  dark  spongy  mass.  Some  oxides,  and  also  some 
sulphates  and  many  phosphates,  are  soluble  entirely  without 
effervescence.  But  many  minerals  resist  decomposition.  It  is 
sometimes  difficult  to  toll  whether  a  mineral  is  decomposed  with 
the  separation  of  the  silica  or  whether  it  is  unacted  upon.  In 
such  a  case  a  portion  of  the  clear  fluid  is  neutralized  by  soda 
(sodium  carbonate),  and  if  anything  has  been  dissolved  it  will 
usually  be  precipitated. 

Test  for  Fluorine. — Most  fluorides  are  decomposed  by  strong 
heated  sulphuric  acid,  give  out  fluorine  which  will  etch  a  glass 
plate  in  reach  of  the  fumes.  The  trial  may  be  made  in  a  lead 
cup  and  the  glass  put  over  it  as  a  loose  cover. 


2.  Trials  with  the  Blowpipe. 

The  blowpipe,  in  its  simplest  form,  is  merely  a  bent  tube  of 
small  size,  eight  to  ten  inches  long,  terminating  at  one  end  in  a 
minute  orifice.  It  is  used  to  concentrate  the  flame  on  a  min- 
eral, and  this  is  done  by  blowing  through  it  while  the  smaller 
end  is  just  within  the  flame. 

The  annexed  figure  represents  the  form  commonly  employed, 
except  that  the  tube  is  usually  without  the  division  at  b.  ft 
contains  an  air  chamber  (o)  to  receive  the  moisture  which  ia 
condensed  in  the  tube  during  the  blowing  ;  the  moisture,  unless 
thus  removed,  is  often  blown  through  the  small  aperture  and 
interferes  with  the  experiment.  The  jet,  e/,  is  movable,  and 
it  is  desirable  that  it  should  be  made  of  platinum,  in  order  that 
it  may  be  cleaned  when  necessary,  either  by  high  heating  or 


CEEMICAL    COMPOSITION    OF   MINERALS. 


83 


_y  immersion  in  an  acid.  The  screw  at  b  is  for  the  purpose  of 
shortening  the  tube  one-half  so  as  to  make  it  more  convenient 
for  the  pocket  of  the  field  mineralogist.  It  is  un- 
screwed for  this  purpose,  and  the  smaller  part  put 
within  the  larger. 

In  using  the  blowpipe  it  is  necessary  to  breathe 
and  blow  at  the  same  time,  that  the  operator  may 
not  interrupt  the  flame  in  order  to  take  breath. 
Though  seemingly  absurd,  the  necessary  tact  may 
easily  be  acquired.  Let  the  student  first  breathe  a 
few  times  through  his  nostrils  while  his  cheeks  are 
inflated  and  his  mouth  closed.  After  this  practice 
lot  him  put  the  blowpipe  to  his  mouth  and  he  will 
find  no  difficulty  in  breathing  as  before  while  the 
muscles  of  the  inflated  cheeks  are  throwing  the  air 
th°iy  contain  through  the  blowpipe.  When  the  air 
is  nearly  exhausted  the  mouth  may  again  be  filled 
through  the  nose  without  interrupting  the  process 
of  blowing. 

The  flame  of  a  candle,  or  a  lamp  with  a  large 
wick  may  be  used,  and  when  so  it  should  be  bent 
in  the  direction  the  flame  is  to  be  blown.     But  it  is  far  better, 
when  gas  can  be  had,  to  use  a  Bunsen's  burner. 

The  flame  has  the  form  of  a  cone,  yellow  without  and  blue 
within.  The  heat  is  most  intense  just  beyond  the  extremity  of 
the  blue  flame.  In  some  trials  it  is  necessary  that  the  air 
should  not  be  excluded  from  the  mineral  during  the  experiment, 
aud  when  this  is  the  case  the  outer  flame  is  used.  The  outer  is 
called  the  oxidizing  flame  (because  oxygen,  one  of  the  consti- 
tuents of  the  atmosphere,  combines  in  many  cases  with  some 
parts  of  the  assay,  or  substance  under  experiment),  and  the  in- 
ner the  reducing  flame.  In  the  latter  the  carbon  and  hydrogen 
of  the  flame,  which  are  in  a  high  state  of  ignition,  and  which  are 
einloeed  from  the  atmosphere  by  the  outer  flame,  tend  to  unite 
with  the  oxygen  of  any  substance  that  is  inserted  in  it.  Hence 
substances  are  red-iced  in  it. 

The  mineral  is  supported  in  the  flame  either  on  charcoal;  or 
\  -f  means  of  steel  forceps  (as  in  the  annexed  figure)  with  plati- 


num  extremities  (a  6),  opened  by  pressiu^r  on  the  pins  pp\  or 
on  platinum  wire  or  foil. 


84  CHEMICAL   PROPERTIES    OF   MINERALS. 

To  ascertain  the  fusibility  of  a  mineral,  the  fragment  for  the 
platinum  forceps  should  not  be  larger  than  the  head  of  a  pin, 
and,  if  possible,  should  be  thin  and  oblong,  so  that  the  extrem- 
ity may  project  beyond  the  platinum.  The  fusible  metals  alloy 
readily  with  platinum.  Hence  compounds  of  lead,  arsenic,  an- 
timony, etc.,  must  be  guarded  against.  These  compounds  are 
tosted  011  charcoal.  The  forceps  should  riot  be  used  with  the 
'luxes,  but  instead  either  charcoal  or  the  platinum  wire  or  foil. 

The  charcoal  should  be  firm  and  well  burnt ;  that  of  soft 
wood  is  the  best.  It  is  employed  especially  for  the  i eduction 
of  oxides,  in  which  the  presence  of  carbon  is  often  necessary, 
and  also  for  observing  any  substances  whicb  may  pass  off  and 
be  deposited  on  the  charcoal  around  the  assay.  These  coatings 
are  usually  oxides  of  the  metals,  which  are  formed  by  the  oxi- 
dation of  the  volatile  metals  as  they  issue  from  the  reduction 
flame. 

The  platinum  wire  is  employed  in  order  to  observe  the  ac- 
tion of  the  fluxes  on  the  mineral,  and  the  colors  which  the 
oxides  impart  to  the  fluxes  when  dissolved  in  them.  The  wire 
used  is  No.  27.  This  is  cut  into  pieces  about  three  inches  long, 
and  the  end  is  bent  into  a  small  loop,  in  which  the  flux  is  fused. 
This  makes  what  is  called  a  bead.  When  the  experiment  is 
complete  the  beads  are  removed  by  uncoiling  the  loop  and  draw- 
ing the  wire  through  the  finger  nails.  After  use  for  awhile  the 
end  breaks  off,  because  platinum  is  acted  upon  by  the  soda,  and 
then  a  new  loop  has  to  be  made.  Dilute  sulphuric  acid  will 
remove  any  of  the  flux  that  may  remain  upon  it  after  a  trial 
has  been  made. 

Glass  tube  is  employed  for  various  purposes.  It  should  be 
from  a  line  to  a  fourth  of  an  inch  in  bore.  It  is  cut  into  pieces 
four  to  six  inches  long,  and  used  in  some  cases  with  both  ends 
open,  in  others  with  one  end  closed.  In  the  closed  tube,  either 
heated  directly  over  the  Bunsen  burner,  or  with  the  aid  of  the 
blowpipe,  volatile  substances  in  the  assay  are  vaporized  and 
condensed  in  the  upper  colder  part  of  the  tube,  where  they 
may  be  examined  by  a  lens  if  necessary,  or  by  further  heating. 
The  odor  given  off  may  also  be  noted,  and  the  acidity  of  any 
ftimeF  bj  inserting  a  small  strip  of  litmus  paper  in  the  mouth 
of  the  tube.  The  closed  tube  is  used  to  observe  all  the  effects 
tlv*t  may  take  place  when  a  substance  is  heated  out  of  contact 
with  the  air.  In  the  open  tube  the  atmosphere  passes  through 
the  tube  in  the  heating,  and  so  modifies  the  result.  The  assay 
is  placed  an  inch  or  an  inch  and  a  quarter  from  the  lower  end 
of  the  tube ;  the  tube  should  be  held  nearly  horizontally,  to 


BLOWPIPE   REACTIONS.  85 

prevent  the  assay  from  falling  out.  The  strength  of  the 
draught  depends  upon  the  inclination  of  the  tube,  and  in  special 
cases  it  should  be  inclined  as  much  as  possible. 

The  most  common  fluxes  are  borax  (sodium  bi-borate),  salt 
of  phosphorus  (sodium  and  ammonium  phosphate),  and  soda 
(sodium  carbonate,  either  the  carbonate  or  bi-carbonate  of  soda 
of  the  shops.)  These  substances,  when  fused  and  highly  heated, 
arc  very  powerful  solvents  for  metallic  oxides.  They  should 
be  pure  preparations.  The  borax  and  soda  are  much  the  most 
important.  In  using  the  platinum  wire,  the  loop  may  be  highly 
heated,  and  then  a  portion  of  the  borax  or  soda  may  be  taken 
up  by  it,  and  by  successive  repetitions  of  this  process  the  re- 
quisite amount  of  the  flux  may  be  obtained  on  the  wire.  Then, 
by  bringing  the  melted  flux  of  the  loop  into  contact  with  one 
or  more  grains  of  the  pulverized  mineral,  the  assay  is  made 
ready  for  the  trial.  With  soda  and  quartz  a  perfectly  clear 
globule  is  obtained,  cold  as  well  as  hot,  if  the  flux  is  used  in 
the  right  proportion.  Some  oxides  impart  a  deep  and  charac- 
teristic color  to  a  bead  of  borax.  In  other  cases  the  color 
obtained  is  more  characteristic  when  salt  of  phosphorus  is  em- 
ployed. The  color  obtained  in  the  outer  flame  is  often  differ- 
ent from  that  which  is  obtained  in  the  inner  flame.  The  beads 
are  sometimes  transparent  and  sometimes  opaque.  If  too  much 
substance  is  employed  the  beads  will  be  opaque  when  it  is  de- 
sired that  they  should  be  transparent.  In  such  cases  the 
experiment  may  be  repeated  with  less  substance.  In  many 
cases  pulverized  mineral  and  the  flux,  a  little  moistened,  are 
mixed  together  into  a  ball  upon  charcoal,  especially  in  the  ex- 
periments with  soda. 

In  the  examination  of  sulphides,  arsenides,  antimonides  and 
related  ores,  the  assay  should  be  roasted  before  using  a  flux,  in 
order  to  convert  the  substance  into  an  oxide.  This  is  done  by 
spreading  the  substance  out  on  a  piece  of  charcoal  and  exposing 
it  to  a  gentle  heat  in  the  oxidizing  flame.  The  sulphur,  arsenic, 
antimony,  etc.,  then  pass  off  as  oxides  in  the  form  of  vapors, 
leaving  the  non-volatile  metals  behind  as  oxides.  The  escap- 
ing sulphurous  acid  gives  the  ordinary  odor  of  burning  sulphur ; 
arsenous  acid,  from  arsenic  present,  the  odor  of  garlic,  or  au 
alliaceous  odor  ;  seleuous  acid,  from  selenium  present,  the  odor 
of  decaying  horse-radish ;  while  antimony  fumes  are  dense  white, 
and  have  no  odor. 

The  following  is  the  scale  of  fusibility  which  has  been  adopted, 
beginning  with  the  most  fusible  : 

1.  STIBNITE. — Fusible  in  large  pieces  in  tUe  candle  flame. 


86  CHEMICAL   PROPERTIES    OF    MINERALS. 

2.  NATROLITE. — Fusible  in   small    splinters   iii   the   candle 
flame. 

3.  ALMANDINE,  or   bright   red    GARNET.— Fusil  ie   in   large 
pieces  with  ease  in  the  blowpipe  flame. 

4.  ACTINOLITE. — Fusible  in  large  pieces  with  difficulty  in  tho 
blowpipe  flame. 

5.  ORTHOCLASE,  or   common    feldspar.       Fusible    in    small 
splinters  with  difficulty  in  the  blowpipe  flame. 

6.  BUONZITE. — Scarcely  fusible  at  all. 

The  color  of  the  flame  is  an  important  character  in  connection 
with  blowpipe  trials.  When  the  mineral  contains  sodium  tho 
color  of  the  flame  is  deep  yellow,  and  this  is  generally  true  in 
spite  of  the  presence  of  other  related  elements.  When  sodium 
(or  soda)  is  absent,  potassium  (or  potash)  gives  a  pale  violet 
color;  calcium  (or  lime)  a  pale  reddish  yellow  ;  lithium,  s,  deep 
purple -red,  as  in  lithia-inica  ;  strontium,  a  bright  red,  this  ele- 
ment being  the  usual  source  of  the  red  color  in  pyrotechny ; 
copper,  emerald  green  ;  phosphates,  bluish  green  ;  boron,  yellow- 
ish green  ;  copper  chloride,  azure  blue.  Beads  should  be  exam- 
ined by  daylight  only,  and  should  be  held  in  such  position  that 
Mie  color  is  not  modified  by  green  trees  or  other  bright  objects 
when  examined  by  transmitted  light.  Colored  flames  are  seen 
to  best  advantage  when  some  black  object  is  beyond  the  flame 
in  the  line  of  vision. 

It  is  also  to  be  noted,  in  the  trials,  whether  the  assay  heats 
up  quietly,  or  with  decrepitation  ;  whether  it  fuses  with  effer- 
vescence or  not,  or  with  intumescence  or  not ;  whether  it  fuses 
to  a  bead  which  is  transparent,  clouded,  or  opaque  ;  whether 
blebby  (containing  air-bubbles  or  not) ;  whether  scoria-like  or 
not. 

Testing  for  Water. — The  powdered  mineral  is  put  at  the 
bottom  of  a  closed  glass  tube,  and  after  holding  the  extremity 
for  a  moment  in  the  flame  of  a  Bunsen's  burner,  moisture,  if 
tiny  is  present,  will  have  escaped  and  be  found  condensed  on  the 
inside  of  the  tube,  above  the  heated  portion.  Litmus  or  tur- 
meric paper  is  used  to  ascertain  if  the  water  is  acid  or  alkaline, 
acids  changing  the  blue  of  litmus  paper  to  red,  and  alkalies  the 
yellow  of  turmeric  paper  to  brown. 

Testing  for  an  Alkali. — If  the  fragment  of  a  mineral,  heated 
in  the  platinum  forceps,  contains  an  alkali,  it  will  often,  after 
being  highly  heated,  give  an  alkaline  reaction  when  placed, 
after  moistening,  on  turmeric  paper,  turning  it  brown.  This 
lest  is  applicable  to  those  salts  which,  on  heating,  part  with  a 
portion  of  their  acid  and  are  rendered  caustic  thereby.  Such 


BLOWPIPE    REACTIONS.  87 

we  the  carbonates,  sulphates,  nitrates,  and  chlorides  of  the 
alkaline  metals. 

Testing  for  Alumina  or  Magnesia, — Cobalt  nitrate,  in  solu- 
tion, is  used  to  distinguish  an  infusible  and  colorless  mineral 
containing  aluminium  from  one  -containing  magnesium.  A 
fragment  of  the  mineral  is  first  ignited,  and  then  wet  with  a 
drop  or  two  of  the  cobalt  solution  and  heated  again.  The  alu- 
minium mineral  will  assume  a  blue  color,  and  the  magnesium 
mineral  a  pale  red  or  pink. 

Any  fusible  silicate,  when  moistened  with  cobalt  nitrate  and 
ignited  will  assume  a  blue  color,  hence  this  test  is  only  deci- 
bive  in  testing  infusible  substances. 

Infusible  zinc  compounds,  when  moistened  with  cobalt  nitrate, 
assume  a  green  color. 

Testing  for  Lithium. — Some  lithium  minerals  give  the 
bright  purple-red  flame  if  simply  heated  in  the  platinum  for- 
ceps. In  other  cases  mix  the  powdered  mineral  with  one  part 
of  fiuorite  and  one  of  potassium  bi-sulphate.  Make  the  whole 
into  a  paste  with  a  little  water,  and  heat  it  on  the  platinum 
wire  in  the  blue  flame. 

Testing  for  Boron. — When  the  bright  yellow-green  of  boron 
is  not  obtained  directly  on  heating  the  mineral  containing  it, 
one  part  of  the  powdered  mineral  should  be  mixed  with  ono 
part  of  powdered  fluorite  and  three  of  potassium  bi-sulphate  ; 
and  then  treated  as  in  the  last.  The  green  color  appears  at  the 
instant  of  fusion. 

Testing  for  Fluorine. — To  detect  fluorine  in  fluorides  mix  a 
little  of  the  powdered  substance  with  potassium  bi-sulphate, 
put  the  mixture  in  a  closed  glass  tube  and  fuse  gently.  The 
bi-sulphate  gives  oft*  half  of  its  sulphuric  acid  at  a  high  temper- 
ature, which  acts  powerfully  on  anything  it  can  attack.  If  a 
fluoride  is  present,  hydrofluoric  acid  will  be  given  off,  and  the 
walls  of  the  tube  will  be  found  roughened  and  etched  when  the 
tube  is  broken  open  and  cleaned  after  the  experiment.  If  a 
silicate  containing  fluorine  be  powdered  and  mixed  with  previ- 
ously fused  salt  of  phosphorus,  and  heated  in  the  open  tube  by 
blowing  thb  flame  into  the  lower  end  of  the  tube,  hydrofluoric 
acid  is  given  off,  and  the  tube  is  corroded  just  above  the  assay. 

Silicates. — Nearly  all  silicates  undergo  decomposition  with 
salt  of  phosphorus,  setting  free  the  silica,  forming  a  bead  which 
is  clear  while  hot  and  has  a  skeleton  of  silica  floating  in  it, 
The  bead  is  sometimes  clear  also  when  cold. 

Iron. — Minerals  containing  much  iron  produce  a  magnetic 
globule  when  highly  heated.  Usually  the  reducing  flame  ia 


88  CHEMICAL    PROPERTIES    OF   MINERALS. 

required,  and  sometimes  the  use  of  soda.  With  borax  iron 
gives  a  bead  with  the  oxidizing  flame  which  is  yellow  while 
hot,  but  colorless  on  cooling,  and  which  in  the  reducing  flame 
becomes  bottle  green. 

Cobalt. — Minerals  containing  cobalt  afford,  with  borax,  a 
beautiful  blue  bead.  If  sulphur  or  arsenic  is  present  it  should 
be  first  roasted  off  on  charcoal. 

Nickel. — In  the  oxidizing  flame  with  borax,  the  bead  i?  violet 
when  hot,  and  red-brown  on  cooling.  In  the  reducing  flame 
the  glass  becomes  gray  and  turbid  from  the  separation  of  metal- 
lic nickel,  and  on  long  blowing,  colorless.  The  reaction  is  ob- 
scured by  the  presence  of  cobalt,  iron,  and  copper. 

Manganese. — With  borax  in  the  oxidizing  flame,  the  bead  is 
a  deep  violet-red,  and  almost  black  if  too  much  of  the  mineral 
is  used.  To  see  the  color  examine  by  transmitted  light.  With 
soda  in  the  same  flame  the  opaque  bead  is  bluish  green. 

Chromium. — With  borax,  both  in  the  oxidizing  and  reducing 
flame,  the  bead  is  bright  emerald  green. 

Titanium. — Titanium  oxide  with  salt  of  phosphorus  on 
platinum  Avire  in  O.F.  dissolves  to  a  clear  glass,  which,  if 
much  is  present,  becomes  yellow  while  hot  and  colorless  on 
cooling;  but  in  R.F.  the  hot  globule  obtained  in  O.F.  reddens 
and  assumes  finally  a  beautiful  violet  color.  On  charcoal  with 
tin  the  glass  becomes  violet  if  there  is  not  too  much  iron 
present. 

Zinc. — Zinc  and  some  of  its  compounds  when  heated  cover 
the  charcoal  with  zinc  oxide,  which  is  yellow  while  hot,  but 
white  on  cooling  ;  and  this  coating,  if  wet  with  cobalt  solution 
and  then  heated,  assumes  a  fine  yellowish-green  color  which 
is  most  distinct  when  cold. 

Lead.,  copper,  tin,  silver,  when  characterizing  a  mineral,  give 
with  soda  in  the  reducing  flame  minute  metallic  globules,  which 
are  malleable,  or  may  be  cut  with  a  knife  ;  they  can  be  distin- 
guished by  their  well-known  physical  properties.  When  two 
or  more  of  these  metals  occur  together,  or  iron  is  also  present^ 
the  globules  consist  usually  of  an  alloy  of  the  metals. 

Lead. — When  the  mineral  is  treated  with  soda  on  charccal 
in  the  oxidizing  flame,  the  yellow  oxide  coats  the  charcoal 
around  the  assay. 

Copper. — The  flame  is  colored,  in  most  cases,  bright  green. 
With  borax  or  salt  of  phosphorus  in  the  reducing  flame  the 
bead  is  red.  In  the  oxidizing  flame  the  bead  is  green  when 
hot  and  becomes  blue  or  greenish  blue  on  cooling. 

Mercury. — Heated  in  the  closed  tube  with  soda,  a  sublimate 
of  metallic  mercury  covers  the  inside  of  the  tube. 


BLOWPIPE    REACTIONS.  89 

Silver. — If  the  silver  is  in  very  small  quantities,  as  in  argen- 
tiferous galena,  the  assay  is  put  into  a  little  cup  made  of  bone 
ashes  (bone  burnt  white  and  finely  pulverized),  and  subjected 
to  the  oxidizing  flame  ;  the  lead  is  oxidized  and  sinks  into  the 
bone  ashes,  leaving  the  silver  a  brilliant  globule  on  the  cupeL 
Before  cupellation  it  is  often  necessary  to  melt  the  assay  to- 
gether with  some  borax  and  pure  lead  in  a  hole  on  charcoal. 
By  this  process  the  sand  and  impurities  are  removed,  and  a 
globule  of  lead  is  obtained  which  contains  all  the  silver,  and 
which  may  be  separated  from  the  slag  and  be  oxidized  as 
above. 

Arsenic. — In  the  closed  tube  arsenic  sublimes  and  coats  the 
tube  with  brilliant  grains,  or  a  crust,  of  metallic  arsenic.  If 
the  mineral  contains  sulphur  as  well  as  arsenic,  sublimates  of 
the  yellow  and  red  arsenic  sulphides  (orpiment  and  realgar)  are 
often  formed.  In  the  open  tube  a  sublimate  of  white  arsenous 
acid  is  formed,  Avhich  condenses  in  bright  crystals  on  the  walls 
of  the  tube,  and  a  strong  garlic  odor  is  given  off.  On  charcoal 
the  alliaceous  odor  is  at  once  perceptible. 

Antimony. — In  the  closed  tube,  when  sulphur  is  present,  the 
assay  yields  a  sublimate  which  is  black  when  hot,  brown-red 
when  cold.  In  the  open  tube  dense  white  vapors  are  given  off 
and  a  white  amorpJwus  sublimate  covers  the  inside  of  the  tube, 
which,  for  the  most  part,  does  not  volatilize  when  reheated. 
On  charcoal  the  assay  yields  dense,  white,  inodorous  fumes. 

Tellurium. — In  the  open  tube  a  white  or  grayish  sublimate 
is  obtained,  which  may  be  fused  to  clear,  colorless  drops.  Ou 
charcoal  a  white  coating  is  produced,  and  the  reducing  flame  is 
colored  green. 

Sulphur. — All  sulphates,  and  other  sulphur-bearing  miner- 
als, when  heated  on  charcoal  with  soda,  produce  a  dark,  yellow- 
ish brown  sulphide  of  sodium ;  and  if  a  fragment  of  this  is 
moistened  and  placed  on  a  polished  plate  of  silver,  it  turns  it 
immediately  brownish  black,  or  black.  Pure  soda,  and  a  flame 
wholly  free  from  sulphur,  is  needed  for  the  trial,  since  the  least 
trace  of  sulphur  in  either  vitiates  the  result.  Many  sulphides 
give  fumes  of  sulphur  on  charcoal.  The  higher  sulphides  afford 
these  fumes  in  a  closed  tube.  The  others  afford  fumes  of  sul- 
phurous acid  in  an  open  tube,  which  redden  a  moistened  bluo 
litmus  paper  placed  in  the  upper  end  of  the  tube. 

Selenium. —  Selenium  and  many  selenides  afford  a  steel-gray 
sublimate  in  an  open  tube,  which  at  the  upper  edge  appears 
red.  On  charcoal  brown  fumes  are  given  off  with  an  odor  like 
that  of  decaying  h(  rse-radish. 


90  CHEMICAL    PROPERTIES    OF   MINERALS. 

Chlorides. — If  a  bead  of  borax  be  saturated  with  copper 
oxide,  and  then  dipped  into  the  powder  of  a  substance  which  ia 
to  be  tested  for  chlorine,  a  chloride  of  copper  is  formed  which 
imparts  an  azure  blue  color  to  the  flame  if  any  chlorine  is  pres- 
ent. If  dissolved  in  water  or  nitric  acid  a  little  silver  nitrate 
produces  a  dense  white  precipitate  of  silver  chloride. 

Nitrates. — A  nitrate,  if  fused  on  charcoal,  will  defkgrate  with 
brilliancy,  owing  to  the  decomposition  of  the  nitrate  and  the 
union  of  its  oxygen  with  the  carbon. 

Phosphates. — Phosphates  give  a  dirty  green  color  to  the  blow- 
pipe flame.  The  color  is  more  distinct  if  the  substance  is  first 
moistened  with  sulphuric  acid.  If  a  phosphate  is  pulverized 
and  heated  in  a  closed  glass  tube  with  some  bits  of  magnesium 
wire,  the  phosphoric  acid  is  reduced,  and  when  the  fusion  is 
moistened  with  water  the  very  disagreeable  odor  of  phosphuretted 
hydrogen  is  obtained. 

For  a  fall  account  of  blowpipe  reactions  recourse  must  be 
had  to  a  treatise  on  the  blowpipe.  The  best  and  fullest  Ameri- 
can work  on  the  subject  is  Prof.  Gr.  J.  Brush's  "  Manual  of  De- 
terminative Mineralogy,  with  an  Introduction  on  Blowpipe 
Analysis." 

In  this  work  the  following  abbreviations  are  used  in  speaking 
)f  blowpipe  reactions : 

B.J3.  =  before  the  blowpipe ;  O.F.  =  oxidizing  flame ; 
R.F.  =  reducing  flame. 


CLASSIFICATION.  93 

4.   DESCRIPTIONS  OF  MINERALS. 

CLASSIFICATION. 

SOME  of  the  prominent  points  in  the  classification  of  minerals 
adopted  in  the  following  pages  are  given  in  connection  with  the 
remarks  on  chemical  composition,  pages  79. 

Many  instructors  in  the  science,  and  most  of  those  who  con- 
sult a  work  on  Mineralogy  for  practical  purposes,  prefer  an  ar- 
rangement of  the  ores  which  groups  them  under  the  head  of  the 
metal  prominent  in  their  constitution.  The  method  of  group- 
ing mineral  species  according  to  the  basic  element  has  therefore 
been  here,  to  a  large  extent,  followed.  An  exception  has  been 
made  in  the  case  of  the  silicates,  because  it  is  with  them  almost 
impracticable,  on  account  of  the  number  of  basic  elements  they 
often  contain ;  and,  moreover,  not  more  than  half  a  dozen  use- 
ful ores  exist  among  them.  The  silicates  therefore,  which  in- 
clude the  larger  part  of  all  minerals,  make  together  one  of  the 
grand  divisions  in  the  classification,  and  they  are  presented  ac- 
cording to  their  natural  groups,  in  the  same  order  as  in  the 
larger  mineralogy. 

The  prominent  subdivisions  in  the  classification  are  as  fol- 
lows : 

I.  THE  ACIDIC  DIVISION,  including  the  acidic  elements  oc- 
curring native,  and  the  native  compounds  of  the  acidic  elements 
with  one  another. 

II.  THE  BASIC  DIVISION,  including  the  basic  elements  occur- 
ring native,  and  the  native  binary  and  ternary  compounds  of 
the  basic  elements — the  silicates  excepted. 

III.  SILICA  and  the  SILICATES. 

IV.  THE   HYDROCARBON  COMPOUNDS,  including  mineral  oils, 
resins,  wax,  and  coals. 

The  following  are  the  chief  subdivisions  under  these  head» : 

I.  ACIDIC  DIVISION. 

1.  Sulphur  Group. — The  chief  oxide  a  trioxide,  its  formula 
K  O3.  Includes  Sulphur  and  sulphur  oxides  ;  Tellurium  and 
tellurium  oxides;  Molybdenum  sulphide  and  oxide;  Tungsten 
oxide. 


92  DESCRIPTIONS   OF   MINERALS. 

2.  Boron  Group. — The  chief  oxide  a    trioxide,  its   formula 
R2  O3.     Includes  compounds  of  Boron  with  oxygen. 

3.  Arsenic  Group. — The  chief  oxide  a  pentoxide,  its  formula 
E,O5.    Includes  Arsenic  arid  arsenic  sulphides  and  oxides  ;  An- 
tii.iony  and  antimony  sulphide,  arsenide  and  oxides ;  Bismuth 
and  bismuth  sulphide,  telluride  and  oxide. 

4.  Carbon  Group. — The  chief  oxide  a  dioxide,  its  formula 
R  O.2.      Includes  Carbon  (Diamond,  Graphite)  and  carbon  diox- 
ide.    (Quartz,  Si  O.2)  belongs  here  chemically,  but  is  placed  with 
the  Silicates.) 

II.  BASIC  DIVISION. 

Gold  ;  Silver  ;  Platinum  and  Iridium  ;  Palladium ;  Quick- 
silver ;  Copper  ;  Lead  ;  Zinc  ;  Cadmium  ;  Tin  ;  Titanium  ;  Co- 
balt and  Nickel ;  Uranium  ;  Iron  ;  Manganese ;  Aluminium  ; 
Cerium,  Yttrium,  Lanthanum,  Didymiurn  and  Erbium  ;  Mag- 
nesium; Calcium;  Barium  and  Strontium;  Potassium  and 
Sodium  ;  Ammonium  ;  Hydrogen. 


III.  SILICA  AND  SILICATES. 

1.  Silica. 

2.  Anhydrous  Silicates. 

1.  Bisilicates. 

2.  Unisilicates. 

3.  Subsilicates. 

3.  Hydrous  Silicates. 

1.  General  section  of  Hydrous  Silicates. 

2.  Zeolite  section. 

3.  Margarophyllite  section. 


IV.  HYDROCARBON  COMPOUNDS. 

1.  Oils,  Resins,  Wax. 

2.  Asphaltum,  Coals. 


GENERAL  REMARKS  ON  ORES. 

An  ore,  in  the  miueralogical  sense  of  the  word,  is  a  mineral 
compound  in  which  a  metal  is  a  prominent  constituent.     In  the 


GENERAL  REMARKS   ON   ORES.  93 

miner's  use  of  the  term  it  is  a  mineral  substance  that  yields,  by 
metallurgical  treatment,  a  valuable  metal,  and  especially  when 
it  profitably  yields  such  a  metal.  In  the  former  sense,  galena, 
the  common  ore  of  lead,  is,  if  it  contains  a  little  silver,  an 
argentiferous  lead-ore ;  while,  in  the  latter,  if  there  is  silver 
enough  to  make  its  extraction  profitable,  it  is  a  silver-ore. 
Further  than  this,  where  a  native  metal,  or  other  valuable 
metallic,  mineral,  is  distributed  intimately  through  the  gangue, 
the  mineral  and  gangue  together  are  often  called  the  ore  of  the 
metal  it  produces. 

We  have  beyond  to  do  with  ores  only  in  the  mineralogical 
sense. 

Ores  are  compounds  of  the  metals,  not  metals  in  the  native 
state.  The  more  common  kinds  are  compounds  of  the  metala 
with  Sulphur  (sulphides) ;  with  Arsenic  (arsenides)  ;  with  Sul- 
phur and  Arsenic  (sulph-arsenides)  ;  with  sulphur  in  ternary 
combination  along  with  arsenic,  antimony  or  bismuth  (making 
compounds  called  sulph-arsenites,  sulph-antimonites,  sulpho-bis- 
mutites) ;  with  Selenium  (selenides) ;  with  Tellurium  (tellu- 
rides)  ;  with  Oxygen  (oxides) ;  with  Chlorine,  Iodine,  or  Bro- 
mine (chlorides,  iodides,  or  bromides) ;  with  oxygen  in  ternary 
combination  with  carbon  (making  carbonates) ;  with  Sulphur 
(making  sulphates) ;  with  Arsenic  (making  arsenates)  ;  with 
Phosphorus  (making  phosphates) ;  with  Silicon  (making  sili- 
cates). 

Gold  and  platinum  are,  with  rare  exceptions,  found  only  na- 
tive, or  intimately  mixed  in  essentially  the  pure  state  with  some 
metallic  minerals.  Tellurium  is  the  only  acidic  element  that 
occurs  combined  with  gold  in  nature. 

Silver  is  found  in  the  state  of  sulphide,  antimonide,  selenide, 
telluride,  sulph-arsenites  and  sulph-antimonites,  but  never  as 
oxide  or  in  oxygen  ternary  compounds. 

Quicksilver  occurs  in  the  state  of  sulphide  (the  common  ore)  ; 
also  in  that  of  selenide  and  sulph-arsenites. 

Copper  and  lead  occur  in  the  state  of  sulphides  (common  ores), 
arid  also  in  all  the  binary  and  ternary  states  mentioned  above. 

Zinc  is  known  in  the  state  of  sulphide  (very  common), 
ojddo,  carbonate,  sulphate,  silicate  (all,  excepting  the  sulphate, 
valuable  as  ores)  ;  and  Cadmium  in  that  of  sulphide  only. 

Tin  occurs  in  the  state  of  oxide  (the  common  ore),  and  sul- 
phide. 

Cobalt  and  Nickel  occur  in  the  states  of  sulphide,  arsenide, 
sulph-arsenides,  antimonide,  oxide,  sulphate,  arsenate,  carbon- 
ate ;  and  nickel  in  that  also  of  a  silicate. 


94  DESCRIPTIONS    OF   MINERALS. 

Iron  occurs  in  the  state  of  sulphide  (very  common,  but  not 
useful  as  an  ore  of  iron),  of  arsenide,  sulph-arsenide,  oxide  (the 
common  ores  of  iron),  carbonate  (useful  ore),  sulphate,  arsen- 
ate,  phosphate,  silicate. 

Manganese  occurs  in  the  state  of  sulphide  (rare),  arsenide 
(rare),  oxide  (the  common  ores),  carbonate,  sulphate,  phosphate^ 
silicate. 


1.  MINEKALS   CONSISTING   OF  THE   ACIDIC 
ELEMENTS. 

Oxygen  might  properly  be  included  in  this  section,  since  it 
occurs  native  in  the  atmosphere  mixed  with  nitrogen,  consti- 
tuting 21  per  cent,  of  it.  But  this  mention  of  it  is  all  that  ia 
necessary.  The  ternary  compounds,  in  which,  as  in  sulphuric 
acid,  hydrogen  is  the  basic  element,  are  here  included.  Chlor* 
ine,  bromine,  and  iodine  do  not  occur  native,  and  neither  do  their 
oxides,  nor  any  compounds  with  acidic  elements,  and  hence  these 
elements  are  not  represented  under  this  division.  The  same  is 
true  of  selenium  and  chromium  of  the  sulphur  group,  and  of 
vanadium,  tantalum,  and  columbium  of  the  arsenic  group. 

I.    SULPHUR  GROUP. 
Native  Sulphur. 

Trimetric. — In  acute  octahedrons,  and    secondaries  to   thii 
form,  with  imperfect  octahedral  cleavage.     1 A 1  (in  same  pyra- 
1.  2. 


mid)  =  10(5°  25'  and  85°  07';  lAl  (over  base)  =  H3C   23'. 
Also  massive. 

Color   and  streak  sulphur-yellow,  sometimes  orange-yellow. 


BULPHUB.  95 

Lustre  resinous.  Transparent  to  translucent.  Brittle.  H.= 
1*5 — 2-5.  G.=  2.07.  Burns  with  a  blue  flame  and  sulphurous 
odor.  In  a  closed  tube  it  is  wholly  volatilized  and  redeposited 
on  the  wall  of  the  tube. 

Native  sulphur  is  either  pure,  or  contaminated  with  clay  or 
bitumen.  It  sometimes  contains  selenium,  and  has  then  an 
orange-yellow  color. 

Diff.  It  is  easily  distinguished  by  its  burning  with  a  blue 
flame,  and  the  sulphur  odor  then  afforded. 

Obs.  The  great  repositories  of  sulphur  are  either  beds  of 
gypsum  and  the  associate  rocks,  or  the  regions  of  active  or  ex- 
tinct volcanoes.  In  the  valley  of  Noto  and  Mazzai  o  in  Sicily, 
at  Conil  near  Cadiz  in  Spain,  Bex  in  Switzerland,  and  Cracow 
in  Poland,  it  occurs  in  the  former  situation.  Sicily  and  the 
neighboring  volcanic  islands,  Vesuvius  and  the  Solfatara  in  its 
vicinity,  Iceland,  Teneriffe,  Java,  Hawaii,  New  Zealand,  De- 
ception Island,  and  most  active  volcanic  regions  afford  more  or 
less  sulphur.  The  native  sulphur  of  commerce  is  brought 
largely  from  Sicily,  where  it  occurs  in  beds  along  the  central 
part  of  the  south  coast  and  to  some  distance  inland.  It  under- 
goes rough  purification  by  fusion  before  exportation,  which 
separates  the  earth  and  clay  with  which  it  occurs. 

On  the  Potomac,  twenty-five  miles  above  Washington,  sul- 
phur has  been  found  associated  with  calcite  in  a  gray  com- 
pact limestone ;  sparingly  about  springs  where  hydrogen  sul- 
phide is  evolved,  in  New  York  and  elsewhere  ;  in  cavities  where 
iron  sulphides  have  decomposed,  and  in  many  coal  mines ;  near 
Borax  Lake,  in  California ;  Inferno,  Humboldt  County,  Nevada, 
abundant. 

The  sulphur  of  commerce  is  also  largely  obtained  from  copper 
and  iron  pyrites,  it  being  given  off  during  the  roasting  of  the»e 
ores. 

Sulphur  when  cooled  from  fusion,  or  above  232°  F.,  crys- 
tallizes in  oblique  rhombic  prisms.  When  poured  into  water 
at  a  temperature  above  300°  F.  it  acquires  the  consistency  of 
soft  wax,  and  is  used  to  take  impressions  of  gems,  medals,  etc., 
which  harden  as  the  sulphur  cools.  The  uses  of  sulphur  for 
gunpowder,  bleaching,  the  manufacture  of  sulphuric  acid,  and 
also  in  medicines,  are  well  known.  Sulphur  occurs  in  various 
ores  as  sulphides  and  sulphates.  Among  the  sulphides  are 
pyrite,  an  iron  sulphide ;  pyrrhotite,  another  iron  sulphide ; 
galena,  a  lead  sulphide,  the  common  ore  of  lead ;  chalcopyrite, 
or  yellow  copper  ore,  a  copper  and  iron  sulphide;  cinnabar,  a 
mercury  sulphide  ;  argentite,  a  silver  sulphide,  etc. 


96  DESCRIPTIONS   OF   MINERALS. 

Sulphuric  and  Sulphurous  Acids. 

Sulphuric  acid  is  occasionally  met  with  around  volcanoes, 
and  it  is  also  formed  from  the  decomposition  of  hydrogen 
sulphide  about  sulphur  springs. 

It  is  intensely  acid.  Composition,  Sulphur  teroxide  (SOJ 
81*6,  water  18-4=100,  it  being  chemically  hydrogen  sul- 
phate. Occurs  in  the  waters  of  Rio  Vinagre,  South  America  ; 
also  in  Java,  and  at  Lake  de  Taal  on  Luzon,  in  the  East 
Indies  ;  in  Genesee  Co.,  N.  Y. ;  and  at  Tuscarora,  St.  Davids, 
and  elsewhere,  Canada  West. 

Sulphurous  acid,  or  sulphur  dioxide  (S0.2),  is  produced 
when  sulphur  burns,  and  causes  the  odor  perceived  during 
the  combustion.  It  is  common  about  active  volcanoes.  It 
destroys  life  and  extinguishes  combustion.  Composition, 
Sulphur  50-00,  oxygen  50-00. 

Native  Tellurium. 

Hexagonal  ;  R/\R  =  86°  57'.  Occurs  sometimes  in 
six-sided  prisms  with  perfect  lateral  cleavage  ;  but  is  com- 
monly granular  massive.  Color  and  streak  tin-white.  Brit- 
tle. H.  =2-2-5.  G.  =6-1-6  -3. 

Sometimes  contains  a  little  iron,  and  also  a  trace  of  gold. 
In  an  open  tube,  b.  B.  yields  a  wrhite  inodorous  sublimate, 
which  may  be  fused  to  colorless  transparent  drops  ;  and  on 
charcoal  fuses  and  volatilizes,  tinging  the  flame  green,  and 
covering  the  charcoal  with  white  tellurium  dioxide. 

Obs.  Occurs  in  Hungary  and  Transylvania  ;  also,  Boulder 
Co.,  Colorado,  at  the  Red  Cloud  Mine  ;  in  Magnolia  District 
at  the  Keystone,  Dun  River,  and  other  mines  ;  in  the  BaJ- 
lerat  District  at  Smuggler  Mine  ;  in  Central  District  at  the 
John  Jay  Mine,  where  masses  of  25  pounds  weight  are  re- 
ported to  have  been  found. 

Tellurium  is  also  a  constituent  of  ores  of  silver  and  lead  (pp.  118,  149), 
and  these  are  the  chief  sources  of  the  metal. 

Tellurite  or  Tellurous  acid,  Te02,  occurs  at  the  Keystone,  Smug- 
gler, and  John  Jay  Mines  ;  especially  the  last,  where  it  is  in  minute 
white  or  yellowish  crystals  having  one  eminent  cleavage. 

Molybdenite. — Molybdenum  Sulphide. 

Hexagonal.  In  hexagonal  plates,  or  masses,  thin  foliated, 
like  graphite,  and  resembling  that  mineral.  H.=  1-1-5. 
G.  =  4-45-4-8.  Color  pure  lead- gray ;  streak  the  same, 


BORON    GROUP.  9? 

slightly  inclined  to  green.  Thin  laminae  very  flexible  ;  not 
elastic ;  leaves  a  trace  on  paper,  like  graphite,  but  its  color 
is  slightly  different,  being  bluish-gray. 

Composition.  Mo  S2=  Sulphur  41-0,  molybdenum  59*0= 
100.  B.B.  infusible,  but  when  heated  on  charcoal,  sulphur 
fumes  are  given  off,  which  are  deposited  on  the  coal.  Dis- 
solves in  nitric  acid,  excepting  a  gray  residue. 

•  Diff.  Resembles  graphite,  but  differs  in  its  paler  color 
and  streak,  and  also  in  giving  fumes  of  sulphur  when  heated, 
as  well  as  by  its  solubility  in  nitric  acid. 

Obs.  Occurs  in  granite,  gneiss,  mica  schist,  and  allied 
rocks  ;  also  in  granular  limestone.  It  is  found  in  Sweden, 
at  Arendal  in  Norway,  in  Saxony,  Bohemia,  at  Caldbeck 
Fell  in  Cumberland,  and  in  the  Cornish  mines. 

In  the  United  States  it  occurs  in  Maine  at  Blue  Hill  Bay, 
Camdage  Farm,  Brunswick,  and  Bowdoinham  ;  in  New 
Hampshire  at  Westmoreland,  Landaff,  and  Franconia ;  in 
Massachusetts  at  Shutesbury  and  Brimfield  ;  in  Connecticut 
at  Haddam  and  Saybrook  ;  in  New  York  near  Warwick ;  in 
New  Jersey  near  the  Franklin  Furnace. 

Molybdenum  does  not  occur  native.  An  oxide  is  occa- 
sionally found  in  yellow  incrustations  on  molybdenite,  as  a 
result  of  its  alteration.  It  occurs,  combined  with  lead,  as  a 
molybdate  (page  151),  and  this  is  the  only  native  salt  con- 
taining it.  The  name  molybdenum  is  from  the  Greek  mo- 
luMaina,  meaning  mass  of  lead,  and  alludes  to  the  resem- 
blance of  molybdenite  to  graphite. 

TUNGSTITE,  or  Tungstic  ochre.  A  yellow  powder  or  incrustation  oc- 
curring with  wolfram,  and  a  result  of  its  decomposition.  Occasionally 
observed  at  Lane's  Mine,  Monroe,  Conn. 

Besides  this  oxide  there  are  tac  native  compounds,  iron  tungstate 
or  wolfram  (p.  183),  lead  tungstate  (p.  151),  and  calcium  tungstate. 
Tungsten  also  occurs  sparingly  in  some  ores  of  columbium,  as  in  cer- 
tain varieties  of  the  minerals  pyrochlore,  columbite,  and  yttro-colum- 
bite. 

II.  BORON  GROUP. 

In  Boron,  as  in  the  Sulphur  group,  the  most  prominent 
oxide  is  a  teroxide. 

Sassolite. — Boracic  Acid.     Sassolin. 

Occurs  in  small  scales,  white  or  yellowish.  Feel  smooth  and 
unctuous.  Taste  acidulous  and  a  little  saline  and  bitter. 


98  DESCRIPTIONS   OF   MINERALS. 

G.  =1*48.  Composition,  H6  06  Bo2  =  Boron  teroxide  56-4, 
water  43-6.  It  is  strictly  hydrogen  borate.  Fuses  easily 
in  the  flame  of  a  candle,  tinging  the  name  at  first  green. 

Found  at  the  crater  of  Vulcano,  and  also  at  Sassoin  Italy, 
whence  it  was  called  Sassolin.  The  hot  vapors  of  the  la- 
goons of  Tuscany  afford  it  in  large  quantities.  The  vapors 
are  made  to  pass  through  water,  which  condenses  them  ;  and 
the  water  is  then  evaporated  by  the  steam  of  the  springs, 
and  boracic  acid  obtained  in  large  crystalline  flakes.  It 
still  requires  purification,  as  the  best  thus  procured  contains 
but  50  per  cent,  of  the  pure  acid.  Occurs  also  in  the  waters 
of  Lick  Springs,  Tehama  Co.,  and  Borax  Lake,  Lake  Co., 
California,  where  it  was  first  observed,  through  their  evapo- 
ration, by  Dr.  J.  A.  Veatch,  in  1856.  It  has  since  been 
obtained  from  the  waters  of  Mono,  Owens,  and  other  lakes. 
It  exists  sparingly  in  the  waters  of  the  ocean.  But  in  all 
these  waters,  it  is  probably  in  combination. 

Boron  occurs  usually  in  the  condition  of  magnesium,  calcium,  and 
sodium  borates  (pp.  206, 212,  227) ;  and  rarely  as  an  iron  borate  (p.  182), 
or  ammonium  borate  (p.  231).  It  also  occurs  in  the  silicates,  tourma- 
line, danburite,  axinite,  and  datolite,  in  which  it  is  easily  detected  by 
the  blowpipe  reaction  (p.  87). 

III.    THE  ARSENIC  GROUP. 

The  elements  of  the  Arsenic  group  occurring  among 
minerals  are,  arsenic,  antimony,  bismuth,  phosphorus,  ni- 
trogen, vanadium,  tantalum,  columbium.  Of  these  arsenic, 
antimony,  and  bismuth  occur  native,  and  as  sulphides  ;  also, 
in  combination  with  other  metals,  constituting  arsenides, 
antimonides,  bismutides  ;  and,  along  with  sulphur  also,  mak- 
ing sulpharsenites,  sulphantimonites,  sulphbismutites.  In 
addition,  they  all,  excepting  bismuth,  enter  into  the  consti- 
tution of  a  series  of  native  ternary  oxygen  compounds  or 
salts,  called  severally,  arsenates,  antimonates,  phosphates, 
nitrates,  vanadates,  tantalates,  columbates. 

The  chief  oxide  has  the  general  formula  K2  05. 

Native  Arsenic. 

Khombohedral.  R/\R=85°  41'.  Cleavage  basal,  imper- 
fect. Also  massive,  columnar,  or  granular. 


THE    ARSENIC    GROUP.  99 

Color  and  streak  tin-white,  but  usually  dark  grayish  from 
tarnish.  Brittle.  H.=3-5.  G.  =5-65-5-95. 

B.B.  volatilizes  very  readily  before  fusing,  with  the  odor 
of  garlic  ;  also  burns  "with  a  pale  bluish  flame  when  heated 
just  below  redness. 

Obs.  Occurs  with  silver  and  lead  ores.  It  is  found  in 
considerable  quantities  at  the  silver  mines  of  Freiberg  and 
Sclmeeberg;  also  in  Bohemia,  the  Hartz,  at  Kapnik  in 
Upper  Hungary,  in  Siberia  in  large  masses,  and  elsewhere. 

In  the  United  States  it  has  been  observed  at  Haverhill 
and  Jackson,  N.  H.,  and  at  Greenwood,  Me. 

Orpiment  — Yellow  Arsenic  Sulphide. 

Trimetric.  Cleavage  highly  perfect  in  one  direction.  In 
foliated  masses,  and  sometimes  in  prismatic  crystals.  Color 
and  streak  fine  yellow.  Lustre  brilliant  pearly,  or  metallic 
pearly,  on  the  face  of  cleavage.  Subtransparent  to  translu- 
cent ;  sectile.  H.  =  1  -5-2.  G.  -  3  -4-3  -5. 

Composition.  As2S3  =  Sulphur  39-0,  arsenic  61*0.  Wholly 
evaporates  before  the  blowpipe  with  an  alliaceous  odor,  and 
on  charcoal  burns  with  a  blue  flame. 

From  Hungary,  Koordistan  in  Turkey  in  Asia,  China,  and 
South  America/  Occurs  at  Edenville,  N.  Y.,  as  a  yellow 
powder,  resulting  from  the  decompositon  of  arsenical  iron. 

Realgar  is  another  arsenic  sulphide.  It  has  a  fine  clear  red  color, 
aurora  red  to  orange,  and  occurs  transparent  or  translucent  ;  H.  = 
15-2;  GK  =335-3  65;  Composition,  As  S= Sulphur  29 '9,  arsenic  70'1. 
Like  the  preceding  before  the  blowpipe.  From  Hungary,  Bohemia, 
Saxony,  the  Hartz,  Switzerland,  and  Koordistan  in  Asiatic  Turkey. 
It  has  been  observed  in  the  lavas  of  Vesuvius. 

Realgar  is  one  of  the  ingredients  of  white  Indian  fire,  often  used  as  a 
signal  light.  Orpiment  is  a  coloring  ingredient  in  the  pigment  called 
king's  yellow,  in  which  it  is  mixed  with  arsenious  acid. 

Arsenolite. — White  Arsenic. 

Isometric.  In  minute  capillary  crystals,  and  botryoidal 
or  stalactitic.  Color  white.  Soluble ;  taste  astringent, 
sweetish.  H.=l-5.  G.=3'7. 

Composition.  As2  03= Arsenic  75-8,  oxygen  24-2  =  100. 

This  is  the  same  compound  with  the  common  arsenic  of 
the  shops.  It  is  found  but  sparingly  native,  accompanying 
ores  of  silver,  lead,  and  arsenic  in  the  Hartz,  Bohemia,  and 
elsewhere.  It  is  a  well-known  poison. 


100  DESCRIPTIONS    OF    MINERALS. 

Claudetite  is  the  same  compound  in  trimetric  crystallizations,  from 
Portugal. 

General  Remarks. — Arsenic  is  obtained  for  commerce  chiefly  from 
arsenopyrite(ormispickel),  an  iron  sulph-arsenide,  and  from  the  nickel 
and  cobalt  arsenides,  by  first  roasting  off  the  sulphur,  and  then  con- 
densing the  arsenic,  in  the  state  of  As2  O3  ("  arsenous  acid  ")  in  large 
chambers.  To  obtain  the  material  pure  it  is  usually  sublimed  again 
in  iron  pots,  in  the  upper  part  of  which  (artificially  kept  cool)  it  is 
condensed,  mostly  in  a  half-fused  vitreous  condition.  To  reduce  the 
oxide  to  the  metallic  state  it  is  heated  with  charcoal.  In  Devon  and 
Cornwall  the  arsenical  ores  occur  with  the  tin  ore,  and  a  large  amount 
of  white  arsenic  is  made.  The  metal  arsenic  forms  a  small  part  of 
some  alloys  ;  the  most  important  is  that  with  lead  for  shot  making. 

Native  Antimony. 

Khombohedral ;  Rf\R—ST  35'.  Usually  massive,  with  a 
very  distinct  lamellar  structure  ;  sometimes  granular.  Color 
and  streak  tin-white.  Brittle.  H.  =  3-3  -5.  G-.  =  6  -6-6  -75. 

Composition.  Pure  antimony,  often  with  a  little  silver, 
iron,  or  arsenic.  B.  B.  on  charcoal  fuses  easily  and  passes 
off  in  white  fumes. 

Obs.  Occurs  in  veins  of  silver  and  other  ores  in  Dauphiny, 
Bohemia,  Sweden,  the  Hartz,  and  Mexico. 

Stibnite. — Gray  Antimony.    Antimony  Sulphide. 

Trimetric.     In  right  rhombic  prisms,  with  striated  lateral 
faces  ;  /  A/=90°  45'.  Cleavage  in  the  direction  of  the  shorter 
diagonal,  highly  perfect.      Commonly  diver- 
gent columnar  or  fibrous.     Sometimes  massive 
granular. 

Color  and  streak  lead-gray ;  liable  to  tarn- 
ish. Lustre  shining.  Brittle  ;  but  thin  lami- 
nae a  little  flexible.  Somewhat  sectile.  II.  =2. 
G.  =4-5-4 -62. 

Composition.  Sb2  S3=  Sulphur  28-2,  anti- 
mony 71*8.  Fuses  readily  in  the  flame  of  a 
candle.  B.  B.  on  charcoal  it  is  absorbed,  giv- 
ing off  white  fumes  and  a  sulphur  odor. 

Diff.  Distinguished  by  its  extreme  fusibility 
and  its  vaporizing  before  the  blowpipe. 
Obs.  Stibnite  occurs  in  veins  with  ores  of  silver,  lead, 
zinc,  or  iron,  and  is  often  associated  with  barite,  spathic 
iron,  or  quartz.  It  occurs  at  Felsobanya  and  Schemnitz  in 
Hungary  ;  at  Wolfsberg  in  the  Hartz  ;  at  Braunsdorf  near 
Freiberg;  in  Auvergne,  Cornwall,  Spain,  and  Borneo. 


THE    ARSENIC    GROUP.  101 

In  the  United  States,  it  has  been  found  sparingly  at  Car- 
mel,  Me.,  Lyme,  N.  H.,  and  at  "Soldier's  Delight,"  Md., 
in  the  Humboldt  mining  region,  and  in  the  mines  of  Aurora, 
Esmeralda  County,  Nevada. 

This  ore  affords  much  of  the  antimony  of  commerce.  By 
simple  fusion,  the  crude  antimony  of  the  shops  is  obtained,, 
from  which  pure  antimony  and  its  pharmaceutical  prepara- 
tions are  made. 

Allemontite  is  an  arsenical  antimony,  Sba  As3,  from  Allemont,  and 
also  from  Bohemia  and  the  Hartz. 

Valentinite.  White  antimony  in  white,  grayish,  or  reddish  rect- 
angular crystals,  with  perfect  cleavage,  affording  a  rhombic  prism  of 
130  58'.  'Also  in  tabular  masses,  and  columnar  and  granular.  H.  = 
2 '5-3.  G.  =5'57.  Lustre  adamantine  to  pearly.  Composition,  Sb203 
=Oxygen  16-44,  antimony  83  56=100. 

Senarmontite  is  the  same  compound  in  isometric  forms. 

Kermesite  or  red  antimony  is  an  antimony  oxide  and  sulphide,  in 
red  tufts  of  capillary  crystals.  Lustre  adamantine.  From  Hungary, 
Dauphiny,  Saxony,  and  the  Hartz. 

Cei-vantite.  An  oxide  of  antimony,  Sb2  O4,  resulting  from  the  de- 
composition of  stibnite. 

Livingstonite.  Like  stibnite,  but  contains  14  per  cent,  of  mercury 
and  has  a  red  streak.  From  Mexico. 

Native  Bismuth. 

Ehombohedral ;  R  A  E— 87°  40'.  Cleavage  rhombohedral, 
perfect.  Generally  massive,  with  distinct  cleavage  ;  some- 
times granular. 

Color  and  streak  silver  white,  with  a  slight  tinge  of  red. 
Subject  to  tarnish.  Brittle  when  cold,  but  somewhat  mal- 
leable when  heated.  H.  =2-2-5.  G.=9'7-9-8.  Fuses  at 
a  temperature  of*£76°  F. 

Composition.  Pure  bismuth,  with  sometimes  a  trace  of 
arsenic,  sulphur  or  tellurium.  B.B.  on  charcoal  vaporizes, 
and  leaves  a  yellow  coating  on  the  coal,  paler  on  cooling. 

Obs.  Native  Bismuth  is  abundant  with  ores  of  silver  and 
cobalt  in  Saxony  and  Bohemia,  and  occurs  also  in  Cornwall 
and  Cumberland,  England.  At  Schneeberg,  it  forms  arbo- 
rescent delineations  in  brown  jasper.  Occurs  also  in  Nor- 
way, Sweden,  Chili  and  Bolivia ;  also  at  the  Balhannah 
mine,  in  S.  Australia,  with  copper  ore  and  gold. 

In  the  United  States,  it  has  been  found  at  Lane's  and 
Booth's  mine,  Monroe,  where  it  occurs  with  tungsten,  galenite 
and  pyrite  ;  also  at  Brewer's  mine,  in  Chesterfield  district, 
South  Carolina  ;  and  in  Colorado. 


102  DESCRIPTIONS    OP   MINERALS. 

Bismuthinite.  A  bismuth  sulphide,  Bia  S3,  in  acicular  crystals  of  a 
lead-gray  color. 

G-uanajuatite.  A  bismuth  selenide,  from  Guanajuato,  Mexico,  called 
also  frenzelite.  Silaonite  is  a  selenide  from  the  same  locality,  of  a 
lead-gray  color. 

Bismite.  Bismuth  ochre,  an  impure  oxide,  grayish,  to  greenish  and 
yellowish  white,  and  massive  or  earthy,  found  with  native  bismuth. 

Tetradymite. — Bismuth  Telluride. 

Hexagonal ;  R  A  R  =  Sl°  2'.  Crystals  often  tubular,  with 
a  very  perfect  basal  cleavage.  Also  massive,  and  foliated 
or  granular.  Laminae  flexible,  and  soil  paper.  Lustre 
splendent  metallic.  Color  pale  steel-gray,  a  little  sectile. 
H.=  1-5—2.  G.=7;2— 7 -9. 

Composition.  Consists  of  bismuth  and  tellurium,  with  some- 
times sulphur  and  selenium,  affording  for  the  most  part  the 
formula  Bi2  (Te,  S)3.  A  variety  from  Dahlonega,  Georgia, 
gave  Tellurium  48-1,  bismuth  51'9  =  Bi,Te3  ;  G.  =  7>642. 
Joseite  is  a  bismuth  telluride  from  Brazil,  in  which  half  the 
bismuth  is  replaced  by  sulphur  ;  and  WeJirlite  is  another 
containing  sulphur,  from  Deutsch  Pilsen,  Hungary,  having 
8=8-44. 

Obs.  Found  with  gold  in  Virginia,  North  Carolina,  and 
Georgia  ;  Highland,  Montana  Territory  ;  Red  Cloud  Mine, 
Colorado  ;  Montgomery  Mine,  Arizona. 

General  Remarks. — The  metal  bismuth  is  obtained  mostly  from 
native  bismuth.  Besides  the  above  ores,  there  are  also  others  in  which 
the  metal  is  combined  with  silver,  lead,  and  cobalt  (pp.  116,  166)  ; 
and  a  carbonate  of  bismuth,  which  occurs  rarely  in  connection  with 
native  bismuth  or  the  ores  of  the  metal,  as  a  result  of  oxidation  ;  also 
a  silicate. 

IV.  CARBON  GROUP. 

The  Carbon  group  in  chemistry  comprises  carbon  and 
silicon,  in  which  the  formula  for  the  most  prominent  oxide 
is  R  02.  Only  carbon  occurs  native. 

Carbon  occurs  crystallized  in  the  diamond  and  graphite  ; 
as  oxides,  in  carbon  oxide,  and  carbon  dioxide  (ordinarily 
called  carbonic  acid);  combined  with  hydrogen,  or  hydrogen 
and  oxygen,  in  bitumen,  mineral  oils,  amber,  and  a  num- 
ber of  native  mineral  resins,  and  mineral  wax;  and  as  the 
chief  constituent  of  mineral  coal,  in  which  it  is  combined 


CARBON   GROUP.  103 

with  more  or  less  of  hydrogen  and  oxygen  and  usually  some 
nitrogen. 

Diamond. 

Isometric.  In  octahedrons,  dodecahedrons  and  more  com- 
plex forms.  Faces  often  curved,  as  in  the  figures.  Cleavage 
octahedral  ;  perfect. 


Color  white,  or  colorless ;  also  yellowish,  red,  orange, 
green,  blue,  brown  or  black.  Lustre  adamantine.  Trans- 
parent;  translucent  when  dark -colored.  H.  =10.  Q.= 
3.48—3-55. 

Composition.  Pure  carbon.  It  burns  and  is  consumed  at 
a  high  temperature,  producing  carbonic  acid  gas.  Exhibits 
vitreous  electricity  when  rubbed.  Some  specimens  exposed 
to  the  sun  for  a  while,  give  out  light  when  carried  to  a  dark 
place.  Strongly  refracts  and  disperses  light. 

Diff.  Diamonds  are  distinguished  by  their  superior  hard- 
ness ;  their  brilliant  reflection  of  light  and  adamantine 
lustre,  their  vitreous  electricity  when  rubbed,  which  is  not 
afforded  by  other  gems  unless  they  are  polished  ;  and,  by  the 
practiced  ear,  by  means  of  the  sound  when  rubbed  together, 

Obs.  The  coarse  diamonds,  unfit  for  jewelry,  are  called 
tort,  and  the  kind  in  black  pebbles,  or  masses,  from  Brazil, 
carbonado.  The  latter  occur  sometimes  in  pieces  1,000 
carats  in  weight ;  they  have  G.  =3  to  3 '42.  Another  kind  is 
much  like  anthracite,  Gr.  =  1  -66,  although  as  hard  as  diamond 
crystals  ;  it  is  in  globules  or  mammillary  masses,  often  partly 
made  up  of  concentric  layers. 

Diamonds  occur  in  India,  in  the  district  between  Golconda 
and  Masulipatam,  and  near  Parma,  in  Bundelcund,  where 
some  of  the  largest  have  been  found ;  also  on  the  Mahanuddy, 


104  DESCRIPTIONS   OF   MINERALS. 

in  Ellore.  In  Borneo,  they  are  obtained  on  the  west  side  of 
the  Ratoos  Mountain,  with  gold  and  platina.  The  Brazilian 
mines  were  first  discovered  in  1728,  in  the  district  of  Serra 
do  Erio,  to  the  north  of  Rio  de  Janeiro  ;  the  most  celebrated 
are  on  the  river  Jeqnitinhonha,  which  is  called  the  Diamond 
River,  and  the  Rio  Pardo  ;  seventy  to  seventy-five  thousand 
carats  are  exported  annually  from  these  regions.  In  the 
Urals  of  Russia  they  had  not  been  detected  till  July,  1829, 
when  Humboldt  and  Rose  were  on  their  journey  to  Siberia. 
The  river  Gunil,  in  the  province  of  Constantine,  in  Africa, 
is  reported  to  have  afforded  some  diamonds. 

In  South  Africa,  where  they  were  first  discovered  in  1867, 
they  occur  in  the  gravel  of  the  Vaal  River,  and  in  the 
Orange  River  country.  The  value  of  the  diamonds  obtained 
up  to  November,  1875,  has  been  estimated  as  exceeding 
60,000,000  of  dollars. 

In  the  United  States,  the  diamond  has  been  met  with  in 
Rutherford  County,  North  Carolina;  Hall  County,  Georgia  ; 
also  Franklin  County,  North  Carolina ;  in  Manchester, 
opposite  Richmond,  Virginia  ;  also  in  Cherokee  Ravine, 
Butte  County,  Forest  Hill  in  El  Dorado  County  (one  weigh- 
ing nearly  5  -62  grains),  Fiddletown  in  Amador  County,  and 
in  Nevada  County,  California;  and  on  the  coast  of  Southern 
Oregon.  It  has  been  reported  from  Idaho. 

The  original  rock  in  Brazil  appears  to  be  either  a  kind  of 
laminated  granular  quartz,  called  itacolumyte  ;  or  a  ferru- 
ginous quartzose  conglomerate.  The  itacolumyte  occurs  in 
the  Urals,  and  diamonds  have  been  found  in  it ;  and  it  is 
also  abundant  in  Georgia  and  North  Carolina.  In  India, 
the  rock  is  a  quartzose  conglomerate.  The  origin  of  the 
diamond  has  been  a  subject  of  speculation,  and  it  is  the 
prevalent  opinion  that  the  carbon,  like  that  of  coal  and 
mineral  oil,  is  of  vegetable  or  animal  origin.  Some  crystals 
have  been  found  with  black  uncrystallized  particles  or  seams 
within,  looking  like  coal ;  and  this  fact  has  been  supposed 
to  indicate  such  an  origin. 

Diamonds,  with  few  exceptions,  are  obtained  from  allu- 
vial Avashings.  In  Brazil,  the  sands  and  pebbles  of  the 
diamond  rivers  and  brooks  (the  waters  of  which  are  drawn 
off  in  the  dry  season  to  allow  of  the  work)  are  collected  and 
washed  under  a  shed,  by  a  stream  of  water  passing  through 
a  succession  of  boxes.  A  washer  stands  by  each  box,  and 
inspectors  are  stationed  at  intervals. 


CARBON    GROUP.  105 

Diamonds  are  valued  according  to  their  color,  transpa- 
rency and  size.  The  rose  diamond  is  more  valuable  than 
the  pure  white,  owing  to  the  great  beauty  of  its  color  and 
its  rarity.  The  green  diamond  is  much  esteemed  on  account 
of  its  color.  The  blue  is  prized  only  for  its  rarity,  as  the 
color  is  seldom  pure.  The  black  diamond,  which  is  uncom- 
monly rare  and  without  beauty,  is  highly  prized  by  collec- 
tors. The  brown,  gray  and  yellow  varieties  are  of  much  less 
value  than  the  pure  white  or  limpid  diamond. 

The  largest  diamond  of  which  we  have  any  knowledge  is 
mentioned  by  Tavernier,  as  in  the  possession  of  the  Great 
Mogul.  It  weighed  originally  900  carats,  or  2,769-3  grains, 
but  was  reduced  by  cutting  to  861  grains.  It  has  the  form 
and  size  of  half  of  a  hen's  egg.  It  was  found  in  1550,  in 
the  mine  of  Colone.  The  diamond  which  formed  the  eye 
of  a  Braminican  idol,  and  was  purchased  by  the  Empress 
Catherine  II.  of  Russia  from  a  French  grenadier  who  had 
stolen  it,  weighs  194|  carats,  and  is  as  large  as  a  pigeon's 
egg.  The  Austrian  crown  has  a  diamond  weighing  139 \ 
carats.  The  Pitt  or  Regent  diamond  is  of  less  size,  it  weighing 
but  136-25  carats,  or  419£  grains  ;  but  on  account  of  its  un- 
blemished transparency  and  color,  it  is  considered  the  most 
splendid  of  Indian  diamonds.  It  was  sold  to  the  Duke  of 
Orleans  by  Mr.  Pitt,  an  English  gentleman,  who  was  gover- 
nor of  Beiicolen,  in  Sumatra,  for  £130,000.  It  is  cut  in  the 
form  of  a  brilliant,  and  is  estimated  at  £125,000.  The 
Rajah  of  Mattan  has  in  his  possession  a  diamond  from  Bor- 
neo, weighing  367  carats.  The  Koh-i-noor,  on  its  arrival 
in  England,  weighed  186-016  carats.*  It  is  said  by  Taver- 
nier to  have  originally  weighed  787-J-  carats.  It  has  since 
been  recut  and  reduced  one-third  in  weight. 

In  the  Dresden  Treasury  there  is  an  emerald  green  dia- 
mond, weighing  31J  carats.  The  Hope  diamond,  weighing 
44jL  carats,  has  a  beautiful  sapphire-blue  color. 

The  diamonds  of  Brazil  are  seldom  large.  Maure  men- 
tions one  of  120  carats,  but  they  rarely  exceed  18  or  20. 
One  weighing  254^  carats,  called  the  "Star  of  the  SoutJt," 
was  found  in  1854. 

Of  South  African  diamonds,   the  "  Schreiner"  weighed, 


*  A  carat  is  a  conventional  weight,  and  is  divided  into  4  grains,  which  are  a  little 
ighter  than  4  grains  troy ;  74  1-1  <>  carat  grains  nre  equal  to  72  troy  grains.  The  term 
carat  is  derived  from  the  name  of  a  bean  in  Africa,  which,  in  a  dried  state,  has  long 
been  used  in  that  country  for  weighing  gold.  These  beans  were  early  carried  to 
India,  and  were  employed  there  for  weighing  diamonds. 


106  DESCRIPTIONS    OF    MINERALS. 

in  its  rough  state,  308  carats ;  and  the  "  Stewart,"  which  has 
a  light  straw  color,  288-35  carats.  The  diamonds  of  South 
Africa  are  mostly  "off  col  or;  "about  10  per  cent,  are  of 
first  quality  ;  15/2d  ;  20,  3d  ;  and  55  per  cent,  are  bort  (W. 
J.  Morton).  The  "Star  of  South  Africa,"  of  pure  water, 
weighed  83-5  carats.  Some  crystals  crack  to  pieces  after 
being  exposed  to  the  air  awhile. 

The  diamond  is  cut  by  taking  advantage  of  its  cleavage,  and 
also  by  abrasion  with  its  own  powder.  The  flaws  are  some- 
times removed  by  cleaving  it.  Afterwards  the  crystal  is  fixed 
to  the  end  of  a  stick  of  soft  solder  when  the  solder  is  in  a 
half-melted  state,  leaving  the  part  projecting  which  is  to  be 
cut.  A  circular  plate  of  soft  iron  is  then  charged  with  the 
powder  of  the  diamond,  and  this,  by  its  revolution,  grinds 
and  polishes  the  stone.  By  changing  the  position,  other 
facets  are  added  in  succession  till  the  required  form  is  ob- 
tained. Diamonds  were  first  cut  in  Europe,  in  1456,  by  Louis 
Berquen,  a  citizen  of  Bruges  ;  but  in  China  and  India,  the  art 
of  cutting  appears  to  have  been  known  at  a  very  early  period. 

By  the  above  process,  diamonds  are  cut  into  brilliant,  rose 
and  table  diamonds.  The  brilliant  has  a  crown  or  upper 
part,  consisting  of  a  large  central  eight-sided  facet,  and  a 
series  of  facets  around  it ;  and  a  collet,  or  lower  part,  of  py- 
ramidal shapes,  consisting  of  a  series  of  facets,  with  a  mailer 
series  near  the  base  of  the  crown.  The  depth  of  a  brilliant 
is  nearly  equal  to  its  breadth,  and  it  therefore  requires  a 
thick  stone.  Thinner  stones,  in  proportion  to  the  breadth, 
are  cut  into  rose  and  table  diamonds.  The  surface  of  the 
rose  diamond  consists  of  a  central  eight-sided  facet  of  small 
size,  eight  triangles,  one  corresponding  to  each  side  of  the 
table,  eight  trapeziums  next,  and  then  a  series  of  sixteen  tri- 
angles. The  collet  side  consists  of  a  minute  central  octagon, 
surrounded  by  eight  trapeziums,  corresponding  to  the  angles 
of  the  octagon,  each  of  which  trapeziums  is  subdivided  by  a 
salient  angle  into  one  irregular  pentagon  and  two  triangles. 
The  table  is  the  least  beautiful  mode  of  cutting,  and  is  used 
for  such  fragments  as  are  quite  thin  in  proportion  to  the 
breadth.  It  has  a  square  central  facet,  surrounded  by  two 
or  more  series  of  four-sided  facets,  corresponding  to  the  sides 
of  the  square. 

Diamonds  have  also  been  cut  with  figures  upon  them.  As 
early  as  1500,  Charadossa  cut  the  figure  of  one  of  the  Fathers 
of  the  church  on  a  diamond,  for  Pope  Julius  II. 


CARBON   GROUP.  107 

Diamonds  are  employed  for  cutting  glass;  and  for  this 
purpose  only  the  natural  edges  of  crystals  can  be  used,  and 
those  with  curved  faces  are  much  the  best.  Diamond  dust 
is  used  to  charge  metal  plates  of  various  kinds  for  jewelers, 
lapidaries  and  others.  Those  diamonds  that  are  unfit  for 
working,  are  sold  for  various  purposes,  under  the  name  of 
lort.  Drills  are  made  of  small  splinters  of  bort,  and  used 
for  drilling  other  gems,  and  also  for  piercing  holes  in  artifi- 
cial teeth  and  vitreous  substances  generally ;  and,  others  of 
iron  set  with  a  few  diamonds,  for  drilling  rocks. 

Graphite. — Plumbago. 

Hexagonal.  Sometimes  in  six-sided  prisms  or  tables  with 
a  transversely  foliated  structure.  Usually  foliated,  and  mas- 
sive ;  also  granular  and  compact. 

Lustre  metallic,  and  color  iron-black  to  dark  steel-gray. 
Thin  lamina  flexible.  R.  =  l-2.  G.=2'25-2-27.  Sofia 
paper,  and  feels  greasy. 

Composition.  Commonly  95  to  99  per  cent,  of  carbon. 
B.B.  infusible,  both  alone  and  with  reagents;  not  acted 
upon  by  acids. 

Diff.  Kesembles  molybdenite,  but  differs  in  being  unaf- 
fected by  the  blowpipe  and  acids.  The  same  characters  dis- 
tinguish the  granular  varieties  from  any  metallic  ores  they 
resemble. 

Obs.  Graphite  (called  also  black  lead]  is  found  in  crys- 
talline rocks,  especially  in  gneiss,  mica  schist  and  granular 
limestone ;  also  in  granite  and  argillyte.  Its  principal  Eng- 
lish locality  at  Borrowdale,  in  Cumberland,  is  now  nearly 
exhausted. 

In  the  United  States  graphite  occurs  in  large  masses  in 
veins  in  gneiss  at  Sturbridge,  Mass.  It  is  also  found  in 
North  Brookfield,  Brimfield  and  Hinsdale,  Mass.  ;  abundant 
at  Roger's  Rock,  near  Ticonderoga  ;  near  Fishkill  Landing  in 
Dutehess  County  ;  at  Rossie,  in  St.  Lawrence  County,  and 
near  Amity,  in  Orange  County,  N.  Y.  ;  at  Greenville,  N.  C. ; 
in  Cornwall,  near  the  Housatonic,  and  in  Ashford,  Ct. ;  near 
Attleboro,  in  Bucks  County,  Penn. ;  in  Brandon,  Vermont ; 
in  Wake,  North  Carolina  ;  on  Tyger  River,  and  at  Spartan- 
burg,  near  the  Cowpens  Furnace,  South  Carolina ;  also 
abundantly  and  of  excellent  quality  in  Canada,  in  Bucking' 
ham,  Fitzroy  and  Grenville. 


108  DESCRIPTIONS    OF    MINERALS. 

For  the  manufacture  of  the  best  pencils  the  granular 
graphite  was  thought  necessary,  and  hence  the  former  great 
value  of  the  Borrowdale  mine,  where  the  texture  was  pecu- 
liarly fine  and  firm.  But  now  the  graphite  is  ground  up, 
and  then  compressed  under  heavy  pressure,  and  thus  the 
fine  texture  and  firmness  required  may  be  obtained  with  any 
pure  graphite.  At  Sturbridge,  Mass.,  it  is  rather  coarsely 
granular  and  foliated,  and  has  been  extensively  worked. 
The  mines  of  Ticonderoga  and  Fishkill  Landing,  N.  Y.  ; 
of  Brandon,  Vt.  ;  and  of  Wake,  North  Carolina,  are  also 
worked  ;  and  that  of  Ash  ford,  Ct.,  formerly  afforded  a  large 
amount  of  graphite,  though  now  the  works  are  suspended. 

Graphite  is  extensively  employed  for  diminishing  the 
friction  of  machinery  ;  also  for  the  manufacture  of  crucibles 
and  furnaces  ;  and  as  awash  for  giving  a  gloss  to  iron  stoves 
and  railings.  For  crucibles  it  is  mixed  with  half  its  weight 
of  clay. 

Carbonic  Acid. 

Carbonic  acid — carbon  dioxide  of  existing  chemistry — is 
the  gas  that  gives  briskness  to  the  Saratoga  and  many  other 
mineral  waters,  and  to  artificial  soda  water.  Its  taste  is 
slightly  pungent.  It  extinguishes  combustion  and  destroys 
life. 

Composition.   C  0,= Oxygen  72-35,  carbon  27 -65  =  100. 

This  gas  is  contained  in  the  atmosphere,  constituting 
about  4  parts,  by  volume,  in  10,000  parts  ;  and  it  is  present 
in  minute  quantities  in  the  waters  of  the  ocean  and  land.  It 
is  given  out  by  animals  in  respiration,  and  is  one  of  the  re- 
sults of  animal  and  vegetable  decomposition  ;  and  from  this 
source  the  waters  derive  much  of  their  carbonic  acid.  This 
gas  is  the  choke-damp  of  mines,  where  it  is  often  the  occasion 
of  the  destruction  of  life.  It  is  often  present  also  in  wells. 

Carbon  dioxide  (or  carbonic  acid)  is  given  out  by  lime- 
stone (or  calcium  carbonate)  when  it  is  heated  ;  and  quick- 
lime is  limestone  from  which  C  0?  has  been  expelled  by  heat, 
a  process  carried  on  usually  in  a  limekiln.  It  is  also  driven 
from  limestone  by  the  action  of  sulphuric  acid,  with  the  for- 
mation of  gypsum  (a  hydrous  calcium  sulphate),  or  anhy- 
drite (an  anhydrous  calcium  sulphate).  These  processes  are 
often  carried  on  in  volcanoes,  and  hence  carbonic  acid  gas  is 
common  in  some  volcanic  regions.  The  Grotto  del  Cane 
(Dog  Cave)  at  the  Solfatara  near  Naples;  is  a  small  cavern 


109 

filled  to  the  level  of  the  entrance  with  this  gas.  It  is  a  com- 
mon amusement  for  the  traveler  to  witness  its  effect  upon  a 
dog  kept  for  that  purpose-.  He  is  held  in  the  gas  awhile  and 
is  then  thrown  out  apparently  lifeless  ;  in  a  few  minutes  he 
recovers  himself,  picks  up  his  reward,  a  bit  of  meat,  and  runs 
off  as  lively  as  ever.  If  continued  in  the  carbonic  acid  gas  a 
short  time  longer,  life  would  have  been  extinct. 

Carbonic  acid,  under  high  pressure,  becomes  a  liquid,  and, 
with  pressure  and  cold,  a  white  snow-like  solid.  In  the  liquid 
state  it  is  often  found  in  microscopic  globules  in  the  inte- 
rior of  crystallized  quartz,  topaz,  and  some  other  mineials  ; 
and  when  this  is  true,  calcite  (calcium  carbonate)  is  often 
present  in  the  same  or  an  adjoining  rock. 

Besides  the  calcium  carbonate  in  nature,  there  are  also 
carbonates  of  ammonium,  sodium,  barium,  strontium,  mag- 
nesium, iron,  manganese,  zinc,  copper,  lead,  nickel,  cobalt, 
bismuth,  uranium,  cerium,  and  lanthanum. 

II.  MINERALS  CONSISTING  OF  THE  BASIC 
ELEMENTS  WITH  OR  WITHOUT  ACIDIC— 
THE  SILICATES  EXCLUDED. 

I.  GOLD. 

Gold  occurs  mostly  native,  being  either  pure,  or  alloyed 
with  silver  and  other  metals.  It  is  occasionally  found  min- 
eralized by  tellurium,  making  part  of  the  valuable  minerals 
Sylvanite,  Nagyagite  and  Petzite.  It  occurs  often  dissemi- 
nated through  pyrite  and  galenite  in  auriferous  regions, 
rendering  these  minerals  valuable  sources  of  gold. 

Native  Gold. 

Isometric.  In  octahedrons,  dodecahedrons  ;  without  cleav- 
age. Also  in  arborescent  forms,  consisting  of  strings  of 
crystals,  filiform,  reticulated,  in  grains,  thin  laminae  and 
masses. 

Color  various  shades  of  gold-yellow,  becoming  pale  from 
alloy  with  silver ;  occasionally  nearly  silver-white  from 
the  silver  present.  Eminently  ductile  and  malleable.  H.  = 
£•5-3.  G.  =12-20,  varying  according  to  the  metals  alloyed 
with  the  gold.  Fuses  at  2,016°  F.  (1,102°  C.) 


110 


DESCRIPTIONS    OF    MIN..KALS. 


Composition.  Native  gold  usually  contains  silver,  and  in 
very  various  proportions  ;  and  the  color  becomes  paler  with 
the  increase  of  silver.  The  finest  •  native  gold  from  Russia 


yielded  gold  98-96,  silver  0-16,  copper  0-35,  iron  0-05  ; 
*G.  =19-099.  A  gold  from  Marmato  afforded  only  73-45  per 
cent,  of  gold,  with  26-48  per  cent,  of  silver;  Gr.=12-666. 
This  last  is  in  the  proportion  of  3  of  gold  to  2  of  silver.  The 
following  proportions  also  have  been  observed  :  3J  to  2  ;  5 
to  2  ;  3  to  1  ;  4  to  1,  and  this  the  most  common  ;  6  to  1  is 
also  of  frequent  occurrence.  Average  of  California  native 
gold  is  88  per  cent,  gold,  and  the  range  mostly  between  87 
and  89;  the  range  of  the  Canadian,  mostly  between  85  and 
90  ;  of  Australian,  between  90  and  96  per  cent.,  and  the 
average  93£.  The  Chilian  gold  afforded  Domeyko  84  to  96 
per  cent,  of  gold,  and  15  to  3  per  cent,  of  silver.  The  more 
argentiferous  gold  has  been  called  Electrum;  the  atomic  pro- 
portion of  1  : 1  between  the  gold  and  silver  corresponds  to 
35-5  per  cent,  of  silver,  and  that  of  2  :  1,  to  21'6  per  cent. 

Copper  is  occasionally  found  in  alloy  with  gold,  and  some- 
times also  iron,  bismuth,  palladium  and  rhodium.  A  rhodium- 
gold  from  Mexico  gave  the  specific  gravity  15 '5-1 6 '8,  and 
contained  34  to  43  per  cent,  of  rhodium.  A  bismuth  gold 
has  been  called  Maldonite. 

Diff.  Iron  and  copper  pyrites  are  often  mistaken  for  gold 
by  those  inexperienced  in  ores  ;  but  these  are  brittle  minerals, 
while  gold  may  be  cut  in  slices,  and  flattens  under  a  hammer. 
Pyrite  is  too  hard  to  yield  at  all  to  a  knife,  and  copper 
pyrites  affords  a  dull  "greenish  powder.  Moreover  pyrite 
gives  off  sulphur  when  strongly  heated,  while  gold  melts 
without  odor. 


GOLD.  HI 

Obs.  Native  gold  is  mostly  confined  to  quartz,  intersect- 
ing in  veins,  or  interlaminated  with,  subcrystalline  slaty  or 
schistose  rocks,  especially  hydromica  and  chloritic  slates.  It 
occurs  sparingly  iu  similar  or  other  veins  in  granite,  gneiss, 
or  mica  slate.  It  has  also  been  found  in  traces,  according 
to  J.  J.  Stevenson,  in  the  trachytes  of  Colorado,  and  in 
Silurian  and  Carboniferous  quartzytes. 

The  quartz  intersects  the  slaty  rocks  in  veins  and  lies  in 
thick  seams  between  their  layers.  It  is  frequently  cellular 
for  a  considerable  distance  from  the  surface  owing  to  the 
alteration  and  removal  of  pyrite,  galena,  or  other  metallic 
ores  that  may  be  accompaniments  of  the  gold,  and  the 
cavities  are  usually  rusty  with  oxide  of  iron,  and  sometimes 
contain  particles  of  sulphur  left  by  the  decomposing  pyrite, 
and  also  strings  or  laminae  of  gold.  The  rock  in  this  cav- 
ernous state  is  rather  easily  quarried  out ;  buc  deep  below, 
where  the  minerals  are  not  removed  by  decomposition,  mining 
is  far  more  difficult. 

Pyrite  itself  is  nearly  as  hard  as  quartz,  when  unaltered, 
and  readily  strikes  fire  with  a  steel.  This  pyrite  is  often 
very  abundant,  and  contains  throughout  it  considerable 
gold ;  but  the  gold  is  so  finely  distributed,  that  little  of  it 
can  be  removed  by  the  ordinary  process  of  crushing  and 
amalgamation ;  nature's  way  consists  in  decomposing  the 
pyrite  and  thereby  making  it  drop  its  load.  The  galenite 
of  a  gold  region  is  also  usually  auriferous. 

Gold  sometimes  occurs  in  the  slate  rocks  adjoining  the 
veins,  though  mostly  confined  to  the  latter.  Auriferous 
quartz  often  contains  no  gold  visible  to  the  naked  eye. 

But  while  quartz  veins  are  to  a  large  extent  the  actual 
repositories  of  the  gold  in  its  native  state,  a  very  large 
part  of  the  gold  derived  from  auriferous  regions  has  come 
from  the  sand  and  gravel  beds,  in  which  it  occurs  in  flat- 
tened grains,  and  sometimes  in  lumps  and  nuggets.  By  dif- 
ferent methods — erosion  by  running  waters,  movements  of 
glaciers,  natural  decomposition,  and  other  disintegrating 
action — the  gold-bearing  rocks  have  been  extensively  re- 
duced to  earth  and  stones,  and  this  loose  material  has  been 
distributed  along  the  river  courses,  making  vast  alluvial  or 
diluvial  gravelly  formations.  From  these  gravels  the  gold 
is  obtained  by  simple  washing,  thus  taking  advantage  of  the 
high  specific  gravity  of  gold.  Streams  are  carried  in  aque- 
ducts and  thrown  in  great  jets  against  the  gravel  bluffs  to 


112  DESCRIPTIONS   OP    MINERALS. 

reduce  the  material  to  loose  earth  and  prepare  it  for  further 
washing  by  the  same  water  in  sluices  arranged  for  the  pur- 
pose. 

The  minerals  most  common  in  gold  regions  are  platinum, 
iridosmine,  magnetite,  pyrite,  galenite,  ilmenite,  chalco- 
pyrite,  blende,  tetradymite,  zircon,  rutile,  barite  ;  also  in 
some  cases  wolfram,  scheelite,  brookite,  monazite  and  dia- 
mond. Platinum  and  iridosmine  accompany  the  gold  of 
the  Urals,  Brazil  and  California ;  and  diamonds  are  found 
in  the  gold  region  of  Brazil,  and  occasionally  in  the  Urals 
and  United  States. 

Gold  is  widely  distributed  over  the  globe.  In  AMERICA, 
it  occurs  in  Brazil  (where  formerly  a  greater  part  of  that 
used  was  obtained)  along  the  chain  of  mountains  which 
runs  nearly  parallel  with  the  coast,  especially  near  Villa 
Rica,  and  in  the  province  of  Minas  Geraes  ;  in  New  Granada, 
at  Antioquia,  Choco  and  Giron ;  in  Chili ;  sparingly  in  Peru 
and  Mexico  ;  in  Arizona ;  in  the  Coast  Range,  and,  much 
more  abundantly,  in  the  Sierra  Nevada,  California  ;  in 
Oregon,  British  Columbia  and  Alaska ;  in  New  Mexico, 
Colorado,  and  Wyoming,  and  other  parts  of  the  Rocky 
Mountain  region  ;  in  the  Appalachians  from  Virginia  to 
Georgia,  a  region  that  formerly  produced  annually  nearly  a 
million  of  dollars  ;  very  sparingly  in  Vermont,  New  Hamp- 
shire, and  other  New  England  States ;  in  Nova  Scotia  ;  in 
Beauce  County,  Canada ;  also,  north  of  Lake  Superior ; 
and  in  the  gravel  of  Illinois  and  Indiana. 

In  EUEOPE,  it  occurs  sparingly  in  Cornwall  and  Devon, 
England  ;  North  Wales,  Scotland,  and  Ireland,  formerly  in 
the  County  of  Wicklow,  where  a  nugget  of  22  ounces  was 
found  ;  and  in  France,  very  sparingly  in  the  Department  of 
Isere  ;  in  the  sands  of  the  Rhine,  the  Reuss,  and  the  Aar ; 
in  Tyrol  and  Salzburg  ;  on  the  southern  slope  of  the  Pen- 
nine Alps,  from  the  Simplon  and  Monte  Rosa  to  the  Valley 
of  Aosta,  Northern  Piedmont,  where  nearly  G,000  ounces 
were  obtained  in  1867  ;  more  abundantly  in  Hungary,  at 
Konigsberg,  Schemnitz  and  Felsobanya,  and  in  Transyl- 
vania, at  Kapnik,  Vorospatak  and  Offenbanya  ;  in  Spain,, 
formerly  worked  in  Asturias  ;  in  Sweden,  at  Edelfors. 

In  the  Urals  are  valuable  mines  at  Beresof,  and  other 
places  on  the  eastern  or  Asiatic  flank  of  this  range,  and  the 
comparatively  level  portions  of  Siberia ;  also  in  the  Altai 
Mountains.  Also  in  the  Cailas  Mountains  in  Little  Thibet  • 


GOLD.  H3 

in  the  rivers  of  Syria  and  other  parts   of  Asia 
inor ;  in  Ceylon,  China,  Japan,  Formosa,  Java,  Sumatra, 
Western  Borneo,  the  Philippines,  and  New  Guinea. 

In  AFRICA,  at  Kordofan,  between  Darfour  and  Abyssinia  ; 
also  south  of  Sahara,  in  the  western  part  of  Africa,  from 
the  Senegal  to  Cape  Palmas  ;  also  along  the  coast  opposite 
Madagascar,  between  the  22d  and  35th  degrees  south  lati- 
tude, in  the  Transvaal  Republic.  Other  regions  are  Tas- 
mania, New  Zealand,  and  New  Caledonia. 

General  Remarks. — The  most  productive  gold  regions  at  the  present 
time  are  those  of  Australia  and  California. 

In  Australia  the  richest  mines  are  those  of  Victoria  and  New  South 
Wales.  Victoria  yielded,  in  1856,  3,000,000  ounces,  and  in  1875,  1,195,- 
250  ;  Australia,  in  1875,  227,000  ounces.  The  Australian  gold  was 
first  made  known  to  the  world  in  1851.  The  localities  discovered 
were  on  Summer  Hill  Creek  and  the  Lewis  Pond  River  (near  lat.  33° 
N.,  long.  149°-150  E.),  streams  which  run  from  the  northern  flank 
of  the  Coriobolas  down  to  the  river  Macquarie,  a  river  flowing  west- 
ward and  northward  ;  it  was  soon  afterward  found  on  the  Turon 
Eiver,  which  rises  in  the  Blue  Mountains  ;  and  finally  a  region  of 
country  1,000  miles  in  length,  north  and  south,  was  proved  to  be 
auriferous  ;  the  country  is  a  region  of  metamorphic  rocks,  granite  and 
slates,  and  in  many  parts  abounds  in  quartz  veins.  Queensland  and 
South  Australia,  and  also  Tasmania  and  New  Zealand,  afford  some 
gold. 

The  first  discovery  of  gold  in  California  was  made  early  in  the 
spring  of  1848,  on  the  American  Fork,  a  tributary  to  the  Sacramento? 
near  the  mouth  of  which  Sutter's  establishment  was  situated.  Soon 
Feather  River,  another  affluent,  18  or  20  miles  north,  was  also  proved 
to  abound  in  gold  about  its  upper  portions  ;  and  it  was  not  long  after 
before  each  stream  in  succession,  north  and  south,  along  the  western 
slope  of  the  Sierra  Nevada  was  found  to  flow  over  auriferous  sands. 
The  gold  as  now  developed  extends  along  that  chain,  through  the 
whole  length  of  the  great  north  and  south  valley  which  holds  the 
rivers  and  plains  of  the  Sacramento  and  San  Joaquin.  It  continues 
south  nearly  to  the  Tejon  pass,  in  latitude  35°,  and  north  beyond  the 
Shasta  Mountains  to  the  Umpqua,  and  less  productively  into  Oregon 
and  Washington  Territories,  and  in  British  Columbia.  Gold  also 
occurs  in  some  places  in  the  coast  range  of  mountains.  Even  the 
very  site  of  San  Francisco  has  been  found  to  contain  traces.  North 
of  Shasta  Mountain  there  are  important  mines  on  the  Klamath  and 
the  Umpqua,  and  some  of  the  best  on  the  sea-shore  between  Gold 
Bluff,  in  41  30  south  of  the  Klamath  (30  miles  south  of  Crescent  City) 
to  the  Umpqua.  What  once  was  Rogue  River  is  now  called  Gold  River. 

In  Colorado,  gold  mines  occur  in  Gil  pin  County,  and  much  less  pro- 
ductively in  Clear  Creek,  Park,  Boulder,  Lake,  Summit,  and  Southern 
counties  ;  and  the  yield  in  1874  amounted  to  $2,102,487,  of  which 
$1,525,447  were  from  Gil  pin  County. 

Nevada  produced  from  the  Comstock  lode  (seep.  123),  in  1875,  gold 
*o  the  amount  of  about  $11, 740, 000,  and  the  rest  of  Nevada,  $2,25G..OOO 


114 


DESCRIPTIONS   OF    MINERALS. 


making  in  all  nearly  $14,000,000  ;  and  in  1876,  the  Comstock  lode 
yielded  $18,000,000,  and  the  rest  of  Nevada  about  $1,338,000.  v 

The  yield  of  the  United  States  in  gold  in  the  years  1870  to  1876,  is 
stated  as  follows  in  a  note  dated  February  5,  1877,  by  J.  J.  Valentine, 
in  Jones's  "  Report  of  the  Silver  Commission  (1877)"  : 

1870..  $33,750,000 

1871 34,398,000 

1872 38,109,395 

1873 39,206,558 

1874 38,466,488 

1875 39,968,194 

1876 42,886,935 

The  amount,  in  1874,  from  California  is  stated  at  $17,620,000  ;  from 
Oregon,  $609,000 ;  Washington,  $155,500  ;  Idaho,  $1,328,430  ;  Mon- 
tana, $2,850,000  ;  Utah,  $92,000  ;  Arizona,  $25,700  ;  Colorado,  $2,- 
102,487  ;  Mexico,  $84,655  ;  British  Columbia,  $1,636,200. 

According  to  the  Report  of  A.  del  Mar,  in  the  ' '  Report  of  the  Sil- 
ver Commission  of  1877,"  the  yield  of  gold  from  all  America  from 
1492  to  the  year  1800,  was  $1,872,300,000.  From  1800  to  1847  inclu- 
sive, 48  years,  the  yield  from  America,  Europe,  and  Africa  is  stated  at 
$42i),200,000  ;  and  from  1848  to  1876  inclusive,  29  years,  $3,381,500,- 
000.  The  largest  annual  amount  was  produced  in  the  year  1856, 
in  which  the  yield  was  $147,600,000  ;  and  next  to  this,  in  1859,  with 
$144,900,000  ;  as  shown  in  the  annexed  table,  giving  the  amounts 
in  millions  of  dollars  : 


1848.. 
1849.. 
1850.. 
1851  . 
1852.. 

1853 155-0 

1854 1'3;-0 

1855 135-0 

1856 147-6 

1857. .       . .133-3 


.  67-5 
,  87-0 
,  93-2 
,120-0 
193-7 


1858 , 
1859 
1850. 
1881 
18I3-3 , 
1833, 
1864. 
1835 
1836 
1837. 


.144-6 
.144-9 
.119-3 
.113-8 
.107-8 
.107-0 
.113-0 
.130-7 
.122-2 
,114-0 


1888. 
1869. 
1870. 
1871. 

187-3. 
1873. 

1874 
1875. 
1876. 


..109-7 
..106-2 
..106-9 
.  1070 
..  99-6 
..  97-2 
..  90-8 
..  97-5 
.  90  0 


The  total  amount  for  these  years  is  $3,381,500,000  The  following 
table  is  taken  from  a  Report  to  the  British  House  of  Commons  in  187( 
— the  amount  for  the  United  States  only  being  corrected  : 


Russia. 

United 

States. 

Mexico  and 
South 
America. 

Australia. 

Other 
Countries. 

Total. 

1850  . 

$16,950,000 

$27,500,000 

1855..  . 
1860  .  . 
1865..  . 
1870..  . 
1875  . 

14,200,000 
15,265,000 
16,135,000 
22.070,000 
20,000,000 

73.700,000 
46,000,000 
53,225,000 
33,750,000 
40,000,000 

$5,000,000 
4,500,000 
4,000,000 
2,500,000 
3,750,000 

$60.325,000 
52,500,000 
44,100,000 
29,150,000 
28,750,000 

$2,500,000 
2.500,000 
2,500,000 
2,500,000 
2,500,000 

$155,725.000 
1-20,  '.65,0(10 
119,960,000 
89,970,000 
95,000,000 

GOLD.  115 

Masses  of  gold  of  considerable  size  have  been  found  in  North  Caro- 
lina. The  largest  was  discovered  in  Cabarrus  County  ;  it  weighed 
28  pounds  avoirdupois  ("  steel-yard  weight,"  equals  37  pounds  troy), 
and  was  8  or  9  inches  long,  by  4  or  5  broad,  and  about  an  inch  thick. 
In  Paraguay,  pieces  from  1  to  50  pounds  weight  were  taken  from  a 
mass  of  rock  which  fell  from  one  of  the  highest  mountains. 

The  largest  masses  of  gold  yet  discovered  have  been  found  in  aurife- 
rous gravel.  The  "  Blanch  Barkley  Nugget,"  found  in  South  Austra- 
lia, weighed  140  pounds,  and  only  six  ounces  of  it  were  gangue  ;  and 
one  still  larger,  the  "  Welcome  Nugget,"  from  Victoria,  weighed 
2,195  ounces,  or  nearly  183  pounds,  and  yielded  £8,376  10s.  M.  sterling 
of  gold.  Two  others  from  Victoria  weighed  1,021,  and  1,105  ounces. 
In  Russia,  a  mass  was  found  in  1842,  near  Miask,  weighing  90  pounds 
troy  ;  another  of  27  pounds,  and  several  of  10  pounds  have  been  found 
in  the  Urals.  The  largest  mass  yet  reported  from  California  weighed 
20  pounds.  A  remarkably  beautiful  mass,  consisting  of  a  congeries  of 
crystals,  weighing  201  ounces  (value  $4,000),  was  found  in  1805,  seven 
miles  from  Georgetown,  in  El  Dorado  County. 

The  origin  of  gold  veins,  or  rather  of  the  gold  in  the  veins,  is  little 
understood.  The  rocks,  as  has  been  stated,  are  metamorphic  slates 
that  have  been  crystallized  by  heat  ;  and  they  are  the  hydromica, 
chloritic,  and  argillaceous,  that  have  been  but  imperfectly  crystal- 
lized, rather  than  the  mica  schist  and  gneiss,  which  are  well  crystal- 
lized ;  and  the  veins  of  quartz  which  contain  the  gold,  occupy  fissures 
through  the  slates,  and  openings  among  the  layers,  which  must  have 
been  made  when  the  metamorphic  changes  or  crystallization  took 
place.  It  was  a  period,  for  each  gold  region,  of  long-continued  heat 
(occupying,  probably,  a  prolonged  age),  and  also  of  vast  upliftings  and 
disturbances  of  the  beds  ;  for  the  beds  are  tilted  at  various  angles, 
and  the  veins  show  where  were  the  fractures  of  the  layers,  or  the  sep- 
arations and  gapings  of  the  tortured  strata.  The  heat  appears  not  to 
have  been  of  the  intensity  required  for  the  better  crystallization  of  the 
more  perfectly  crystalline  schists.  The  quartz  veins  could  not  have 
been  filled  from  below,  by  injection  ;  they  must  have  been  filled 
either  laterally,  or  from  above.  In  all  such  conditions  of  upturning 
and  metamorphism,  the  moisture  present  would  have  become  intensely 
heated,  and  hence  have  had  great  dissolving  and  decomposing  power  ; 
it  would  have  taken  up  silica  with  alkalies  from  the  rocks  (as  happens 
in  all  Geyser  regions),  along  with  whatever  other  mineral  substances 
were  capable  of  solution  or  removal  ;  and  the  vapor,  thus  laden, 
would  have  filled  all  open  spaces,  there  to  make  depositions  of  the 
silica  and  ether  ingredients  it  contained.  These  mineral  ingredients 
would  have  been  derived  either  from  the  rock  adjoining  the  veins  or 
opened  spaces,  or  from  depths  below  through  ascending  vapors.  By 
one  or  both  of  these  means,  the  quartz  must  have  received  its  gold, 
pyrite,  and  ores  of  lead,  copper  and  other  materials— all  having  been 
carried  into  the  open  cavities  at  the  same  time  with  the  silica  or 
quartz.  The  pyrite  of  the  vein  is  usually  auriferous,  showing  that  it 
was  crystallized  under  the  same  circumstances  that  attended  the  de- 
positing of  the  gold  in  strings,  crystals,  and  grains  ;  and  the  same  is 
often  true  of  the  galena. 

Calavcrite  is  a  bronze-yellow  gold  telluride.      AuTe4= Tellurium 


LI 6  DESCRIPTIONS   OF   MINERALS. 

55'5,  gold  44-5=100,  with  a  little  silver,  occurring  massive  at  the  Stan, 
islaus  Mine,  California,  and  the  Red  Cloud  Mine,  Colorado,  and  also 
the  Keystone  and  Mountain  Lion  mines,  in  the  Magnolia  District. 

Krennerite  is  another  gold  telluride. 

Sylvanite,  called  also  Graphic  tellurium,  is  a  telluride  of  gold  and 
silver,  also  containing  sometimes  antimony  and  more  or  less  lead  (see 
p.  118). 

Nagyagite  is  a  telluride  of  lead  containing  9  to  13  per  cent,  of  gold 
(see  p.  149). 

Petzite  is  a  telluride  of  silver,  allied  to  Hessite  (p.  118^,  containing 
gold  ;  a  specimen  from  Golden  Rule  Mine,  Colorado,  contained  25-60 
per  cent,  according  to  Genth. 


II.  SILVER. 

Silver  occurs  native,  and  alloyed,  or  combined  with  gold  ; 
also  combined  with  sulphur,  selenium,  tellurium,  arsenic, 
antimony,  bismuth,  chlorine,  bromine,  or  iodine ;  but  nevei 
as  an  oxide,  carbonate,  sulphate,  or  phosphate. 

Native  Silver. 

Isometric.  In  octahedrons  and  other  forms.  No  cleavage 
apparent.  Occurs  often  in  filiform  and  arborescent  shapes, 
the  threads  having  a  crystalline  character  ;  also  in  laminae, 
and  massive. 

Color  and  streak  silver-white  and  shining.  Often  black 
externally  from  tarnish.  Sectile.  Malleable.  H.  =2-5-3. 
G.=  10  -1-11-1. 

Composition.  Native  silver  is  usually  an  alloy  of  silver 
and  copper,  the  latter  ingredient  often  amounting  to  10  per 
cent.  It  is  also  alloyed  with  gold,  as  mentioned  under  that 
metal.  A  bismuth  silver  from  Copiapo,  S.  A.,  contained  16 
per  cent,  of  bismuth. 

B.B.  fuses  easily  to  a  silver- white  globule.  Dissolves  in 
nitric  acid,  from  which  it  is  precipitated  as  white  chloride 
on  adding  hydrochloric  acid.  A  clean  plate  of  copper  im- 
mersed in  the  nitric  solution  becomes  coated  with  silver. 

Diff.  Distinguished  by  being  malleable  ;  from  bismuth 
and  other  white  native  metals  by  affording  no  fumes  before 
the  blowpipe  ;  by  affording  a  precipitate  with  hydrochloric 
acid  which  becomes  black  on  exposure. 

Obs.  Native  silver  occurs  in  masses  and  string-like  ar- 
borescences,  penetrating  the  gangue,  or  its  minerals,  in 


SILVER.  117 

various  silver  mines.  It  is  also  found  mixed  with  native 
copper. 

The  mines  of  Norway,  at  Kongsberg,  formerly  afforded  mag- 
nificent specimens  of  native  silver,  but  they  are  now  mostly 
under  water.  One  specimen  from  this  locality,  at  Copenha- 
gen, weighs  five  hundred  pounds ;  and  two  other  masses 
have  been  found  weighing  238  and  436  pounds.  Other  Eu- 
ropean localities  are  in  Saxony,  Bohemia,  the  Hartz,  Hun- 
gary, Dauphiny.  Peru  and  Mexico  also  alford  native  silver. 
A  Mexican  specimen  from  Batopilas,  weighed  when  obtained 
403  pounds  ;  and  one  from  Southern  Peru  (mines  of  Huan- 
tajaya)  weighed  over  8  cwt.  Arizona  is  reported  to  have 
produced  one  mass  weighing  2,700  pounds.  In  the  United 
States,  in  the  Lake  Superior  region,  the  silver  generally  pen- 
etrates the  copper  in  masses  and  strings,  and  is  very  nearly 
pure,  notwithstanding  the  copper  about  it.  Large  masses 
occur  at  the  Idaho  Silver  Mine,  called  the  Poor  Man's  Lode  ; 
and  in  strings  it  is  occasionally  found  in  the  mines  of  Ne- 
vada, California,  and  Colorado. 

Much  of  the  galena  of  the  world  contains  a  very  small  per- 
centage of  silver  ;  that  of  Monroe,  Conn.,  yields  nearly  3 
per  cent. 

Native  silver  has  also  been  observed  near  the  Sing  Sing 
state  prison ;  at  the  Bridgewater  copper  mines,  N.  J.  ;  and 
in  handsome  specimens  at  King's  Mine,  Davidson  County, 
North  Carolina. 

Native  Amalgam  is  a  compound  of  silver  and  mercury.  The  com- 
pounds AgHg  =  Silver  35*1,  mercury  64'9,  or  Ag2  H3  =  Silver  26'5, 
mercury  73  5,  are  included.  Another  from  Chili  having  the  formula 
Ag12Hgand  containing  86 '6  per  cent,  of  silver  has  been  called  AT- 
querite;  and  still  another  Ag]8  Hg,  Kongsbergite. 

Argentite. — Silver  Glance.     Sulphuret  of  Silver. 

Isometric.  In  dodecahedrons  more  or  less  modified. 
Cleavage  sometimes  apparent  parallel  to  the  faces  of  the 
dodecahedron.  Also  reticulated  and  massive. 

Lustre  metallic.  Color  and  streak  blackish  lead-gray  ; 
streak  shining.  Verysectile.  H.=  2-2'5.  G.-7-19- 
7-4. 

Composition.  When  pure,  Ag2S  =  Sulphur  12-9,  silver 
87'1.  B.B.  on  charcoal  in  O.F.  it  intumesces,  gives  oif  the 
odor  of  sulphur,  and  finally  affords  a  globule  of  silver. 

Diff.  Resembles  some  ores  of  copper  and  lead,  and  other 


118  DESCRIPTIONS   OF   MINERALS. 

ores  of  silver,  but  is  distinguished  by  being  easily  cut,  like 
lead,  with  a  knife  ;  and  also  by  affording  a  globule  of  silver 
on  charcoal,  by  heat  alone.  Its  specific  gravity  is  much 
higher  than  that  of  any  copper  ores. 

Obs.  This  important  ore  of  silver  occurs  in  Europe  prin- 
cipally at  Annaberg,  Joachimstahl,  and  other  mines  of  the 
Erzgebirge ;  at  Schemnitz,  and  Kremnitz,  in  Hungary,  and 
at  Freiberg  in  Saxony.  It  is  a  common  ore  at  the  Mexican 
silver  mines,  and  also  in  the  mines  of  South  America.  It 
occurs  in  Arizona,  with  chalcocite,  at  the  Heintzelman  Mine, 
and  in  Nevada. 

A  mass  of  "sulphuret  of  silver"  is  stated  by  Troost  to- 
have  been  found  in  Sparta,  Tennessee. 

Acanthite  is  a  trimetric  sulphide  of  silver,  Ag2S,  from 
Joachimstahl ;  and  Daleminzite,  another,  from  near  Frei- 
berg. 

Stromeyerite.  A  steel-gray  sulphide  of  silver  and  copper,  Ag2S 
+  Ciij  S  =  Sulphur  15-7,  silver  53'1,  copper  31-2  =  100.  G.=  fr26. 
B.B.  it  fuses  and  gives  in  the  open  tube  an  odor  of  sulphur ;  but  a 
silver  globule  is  not  obtained  except  by  cupellation  with  lead.  From 
Peru,  Silesia,  Chili,  Siberia,  and  Arizona. 

Sternbergite.  A  sulphide  of  silver  and  iron  containing  33  per  cent, 
of  silver.  It  is  a  highly  foliated  ore  resembling  graphite,  and  like  it 
leaving  a  tracing  on  paper  ;  the  thin  laminae  are  flexible  ;  color  pinch- 
beck brown  ;  streak  black.  From  Joachimstahl  and  Johanngeorgen- 
stadt. 

Naumannite.  A  selenide  of  silver  and  lead  in  iron -black  cubes  and 
massive  ;  G.  =8  ;  contains  73  per  cent,  of  silver.  From  the  Hartz. 

Hessite.  A  telluride  of  silver,  Ag2  Te= Tellurium  37-2,  silver  62-8  = 
100.  Color  between  lead-gray  and  steel-gray.  Sectile.  G.  =8*3 — 8'6. 
B.B.  in  the  open  tube,  faint  sublimate  of  tellurous  acid;  on  char- 
coal with  soda  a  silver  globule.  From  the  Altai ;  at  Nagyag  and 
Retzbanya ;  Coquimbo,  Chili ;  Calaveras  Co. ,  Cal. ;  Red  Cloud  Mine, 
Colorado  ;  Kearsarge  Mine,  Dry  Canyon,  Utah. 

Petzite  is  a  hessite  with  the  silver  replaced  in  part  by  gold.  G.  = 
8 '7-9 '4.  Between  steel-gray  and  iron -black.  Variety  from  Golden 
Rule  Mine,  afforded  Genth  Tellurium  32 '68,  silver  41 '86,  gold  25  60= 
10014.  Occurs  at  the  same  localities  with  hessite. 

Tapalpite  is  a  telluride  of  bismuth  and  silver  from  Mexico. 

Syfoanite  or  Graphic  Tellurium,  A  telluride  of  gold  and  silver 
(Ag,  Au)  Tea = (if  Ag  :  Au=l  :  1)  Tellurium  55 '8,  gold  28'5,  silver  15'7 
=  100.  Color  and  streak  steel-gray  to  silver- white,  and  sometimes  nearly 
brass-yellow.  H.=l'5-2.  G.=7'99-8'33.  Called  graphic  because  of 
a  resemblance  in  the  arrangement  of  the  crystals  to  writing  charac- 
ters. From  Transylvania  ;  Calaveras  Co. ,  California  ;  Red  Cloud  and 
Grand  View  Mines,  Colorado. 

Eucairite.  A  selenide  of  silver  and  copper,  containing  42-45  per 
cent,  of  silver ;  color  between  silver- white  and  lead-gray  ;  easily  cut 
by  the  knife.  .  From  Sweden  and  Chili. 


SILVER.  119 

Dyscrasite,  or  Antimonicd  Silver,  consists  simply  of  silver  and  anti- 
mony (78  parts  to  22=Ag4  Sb),  and  has  nearly  a  tin-white  color. 
G.—  9'4-9'8.  B.B.  fumes  of  antimony  pass  off,  leaving  finally  a 
globule  of  silver.  From  Wolfach,  Wittichen,  Andreasberg  ;  also 
Allemont  in  Dauphiny  ;  and  Bolivia,  S.  A. 

Pyrargyrite.—  Ruby  Silver.    Dark  Red  Silver  Ore. 


Ehombohedral.      ^72  =  108°   42;    E/^i-2  =  129°   39'. 
Cleavage  parallel  to  R  imperfect.     Also  massive.     Black  to 
dark  cochineal-red,  with  the  streak  cochi- 
neal-red and  lustre  splendent  metallic-ada- 
mantine.    H.  =  2-2  -5,  G.  =  5  -7-5  -9. 

Composition.  Ag3S3Sb  (=3  Ag2S  +  Sb3 
S,)  =  Sulphur  17*7,  antimony  22  -5,  silver 
59-8  =  100. 

B.  B.   fuses    very  easily  ;   on   charcoal   a 
white  deposit  of  antimony  oxide  is  deposited, 
and  with  soda  a  globule  of  silver  is  obtained.     In  an  open 
tube  gives  off  sulphurous  fumes  that  redden  litmus  paper. 

Diff.  Its  red  streak,  and  its  reactions  for  antimony  and 
silver,  are  distinctive. 

Obs.  Occurs  at  Andreasberg  ;  also  in  Saxony,  Hungary, 
Cornwall,  Mexico,  Chili  ;  in  Nevada  at  Washoe  ;  abundant 
about  Austin,  Reese  River  ;  at  Poor  Man's  Lode,  Idaho. 

Proustite,  or  Light  Red  Silver  Ore,  is  a  related  ore  con- 
taining arsenic  in  place  of  much  or  all  of  the  antimony. 
Composition,  Ag3  Ss  As  =  Sulphur  19-4,  arsenic  15*1,  silver 
65-5  =  100.  G.=5-4-5-56. 

B.  B.  gives  a  garlic  odor. 

Occurs  with  pyrargyrite  at  the  above-mentioned  localities. 

Stephanite.—  Brittle  Silver  Ore.     Black  Silver. 

Trimetric.  7A  7=115°  39'.  No  perfect  cleavage.  Often 
in  compound  crystals.  Also  massive.  Streak  and  color 
iron-black.  II.  =  2-2  -5.  G.  =  6  -27. 

Composition.  Ag5  S4  Sb  (  =  5  Ag2  S  +  Sb2  S3)  =  Sulphur 
16-2,  antimony  15*3°,  silver  68*5.  B.B.  it  gives  an  odor  of 
sulphur  and  also  fumes  of  antimony,  and  yields  a  dark 
metallic  globule,  from  which  silver  may  be  obtained  by  the 
addition  of  soda.  Soluble  in  dilute  nitric  acid,  and  the  solu- 
tion indicates  the  presence  of  silver  by  silvering  a  plate  of 
copper. 


120  DESCRIPTIONS    OP   MINERALS. 

Obs.  It  occurs  with  other  silver  ores  at  Freiberg,  Schnee- 
berg,  and  Johanngeorgenstadt,  in  Saxony ;  also  in  Bohe- 
mia, and  Hungary.  It  is  an  abundant  ore  in  Chili,  Peru, 
and  Mexico,  and  also  in  Nevada,  and  at  the  Comstock  Lode, 
and  at  Ophir,  and  Mexican  mines,  in  the  Reese  Eiver  and 
Humboldt,  and  other  regions ;  in  Colorado  and  Idaho.  It  is 
sometimes  called  black 


Polybasite  is  near  stephanite  in  color,  specific  gravity,  and  composi- 
tion, but  contains  some  arsenic  and  copper,  with  64  to  72*2  per  cent,  of 
silver.  The  crystals  are  trimetric,  and  usually  in  tabular  hexagonal 
prisms,  without  distinct  cleavage.  G.  =6,214.  From  Freiberg,  Przi- 
brarn  ;  Mexico  and  Chili;  the  Reese  mines  in  Nevada,  and  Idaho. 

Miargyrite  is  an  antimonial  silver  sulphide,  containing  but  36 '5  per 
cent,  of  silver,  and  having  a  dark  cherry-red  streak,  though  iron-black 
in  color.  B.B.  on  charcoal  gives  off  fumes  of  antimony  and  an  odor 
of  sulphur  ;  and  in  the  oxidating  flame,  a  globule  is  left  which  finally 
yields  a  button  of  pure  silver. 

Brongniardite  occurs  in  regular  octahedrons  and  massive,  grayish- 
black  in  color,  and  contains  about  25  per  cent,  of  silver,  with  lead,  an- 
timony, and  sulphur  G.=5'95.  From  Mexico. 

Polyargyrite  also  is  isometric,  having  cubic  cleavage,  and  is  from 
Wolf ach  in  Baden.  It  is  near  polybasite  in  composition = 12 Ag2  S  + 
Sb?  S3. 

Freieslebenite  is  a  monoclinic  antimonial  silver-and-lead  sulphide,  of 
a  light  steel-gray  color,  with  G.  =6-G'4.  Contains  22  to  24  per  cent, 
of  silver.  From  Saxony,  Transylvania,  and  Spain. 

Pyrostilpnite  is  another  monoclinic  silver  ore  ;  its  delicate  crystals 
are  grouped  like  stilbite  and  have  a  fire-red  color.  Contains  62 '3  per 
cent,  of  silver.  From  Freiberg,  Andreasberg,  and  Przibram. 

Cerargyrite. — Horn  Silver.     Silver  Chloride. 

Isometric.  In  cubes,  with  no  distinct  cleavage.  Also 
massive,  and  rarely  columnar ;  often  incrusting.  Color 
gray,  passing  into  green  and  blue  ;  looks  somewhat  like  horn 
or  wax,  and  cuts  like  it.  Lustre  resinous,  passing  into  ada- 
mantine. Streak  shining.  Translucent  to  nearly  opaque. 

Composition.  Ag  Cl= Chlorine  24-7,  silver  75-3.  Fuses 
in  the  flame  of  a  candle,  and  emits  acrid  fumes.  B.B.  af- 
fords silver  easily  on  charcoal.  The  surface  of  a  plate  of 
iron  rubbed  with  it  is  silvered. 

Obs.  A  very  common  ore  and  extensively  worked  in  the 
mines  of  South  America  and  Mexico,  where  it  occurs  with 
native  silver  ;  and  also  abundant  in  Nevada  about  Austin, 
Lander  Co.  ;  in  Idaho  at  Poor  Man's  Lode  ;  occurs  also  in 
Comstock  Lode  ;  and  in  Arizona  ;  also  at  the  mines  of  Sax- 
ony, Siberia,  Norway,  the  Hartz,  and  Cornwall. 


SILVER.  121 

Bromyrite  or  Bromic  Silver.  Silver  united  with  bromine.  Ag  Br— 
Bromine  42  *6,  silver  5  7 '4= 100.  Occurs  with  the  preceding  in  Mexico 
and  Chili. 

Embolite.  A  chlorobromide  of  silver,  resembling  the  chloride  or  horn 
silver.  Color  asparagus  to  olive  green.  Contains  51  of  chloride  of  sil- 
ver, to  49  of  bromide.  This  ore  is  not  less  common  in  Chili  than  the 
chloride.  It  has  also  been  found  in  Chihuahua,  Mexico. 

lodyrite.  A  silver  iodide,  Ag  I=Iodine  54*0,  silver  4G'0=100.  It 
has  a  bright  yellow  color.  From  Spain,  Chili,  Mexico,  and  the  Cerro 
Colorado  Mine  in  Arizona. 

Tocornalite.     A  silver-and-mercury  iodide  from  Chili. 

General  Remarks. — The  chief  sources  of  the  silver  of  commerce  ara 
(1)  Native  silver  ;  (2)  the  sulphide,  Argcntite  (or  vitreous  silver),  com- 
mon in  Mexico,  and  also  in  the  Humboldt,  lieese  River  mining  dis- 
tricts ;  four  species  among  the  sulpharsenites  and  sulphantimonites, 
viz.,  (3)  Proustite  or  the  light  red  or  ruby  silver  ore,  and  (4)  Pyrar- 
gyrite,  or  dark  red  silver  ore,  both  common  in  Chilian,  Peruvian, 
and  Mexican  mines  ;  (5)  Freieslebenite ;  (6)  Argentiferous  tetrahedrite, 
which  contains  sometimes  10  to  30  per  cent,  of  silver,  abundant  at 
some  Humboldt  County,  Nevada,  mines,  at  Colorado  silver  mines,  and 
at  various  Chilian,  Bolivian  and  Mexican  mines,  as  well  as  in  some 
silver  mines  of  Europe  ;  (7)  Stephanite  or  brittle  silver  ore,  common  in 
Nevada,  Colorado,  and  at  the  Washoe  mines,  Western  Utah  ;  (8)  the 
chloride,  called  horn-silver  or  Cerargyrite,  common  in  Chili,  Mexico, 
Idaho ;  (9)  the  bromide  and  chlorobromide,  Bromyrite  and  Embo- 
lite, common  in  Chili  and  Mexico,  especially  the  latter,  along  with 
the  rarer  iodide  ;  (10)  Argentiferous  Galcnite,  the  lead  ore,  galenite, 
even  when  containing  but  5  ounces  of  silver  to  the  ton,  being  profita- 
bly worked  for  its  silver.  The  other  ores  of  silver  mentioned  beyond 
are  seldom  of  great  abundance.  The  most  important  of  them  are  sil- 
ver  amalgam  or  Arquerite,  common  especially  in  Chili,  and  Polybasite. 

Silver  ores  occur  in  rocks  of  various  ages,  in  gneiss  and  allied  rocks, 
in  porphyry,  trap,  sandstone,  limestone,  and  shales ;  and  the  sand- 
stone and  shales  may  be  as  recent  as  the  Tertiary.  The  veins  often, 
intersect  trachytic,  porphyry,  and  other  eruptive  rocks,  or  the  sedi- 
mentary formations  in  the  vicinity  of  such  rocks,  and  have  owed  their 
existence  in  many  cases  to  the  heat,  fracturing,  and  vapors  from 
below,  attending  the  eruptions. 

Silver  ores  are  associated  often  with  ores  of  lead,  zinc,  copper,  co- 
balt, and  antimony,  and  the  usual  gangue  is  calcite  or  quartz,  with 
frequently  fluor  spar,  pearl  spar,  or  heavy  spar. 

The  silver  of  South  America  is  derived  principally  from  the  horn 
silvers,  stephanite,  ruby  silver,  vitreous  silver  ore,  and  native  silver. 
Those  of  Mexico  are  of  nearly  the  same  character.  Besides,  there  are 
earthy  ores  called  color  ados,  and  in  Peru  pacos,  which  are  mostly 
earthy  oxide  of  iron,  with  a  little  disseminated  silver  ;  they  are  found 
near  the  surface  where  the  rock  has  undergone  partial  decomposition. 
The  sulphides  of  lead,  iron,  and  copper  of  the  mining  regions,  gene- 
rally contain  silver,  and  are  also  worked. 

In  South  America  the  Chilian  mines  are  on  the  western  slope  of  the 
Cordilleras,  and  are  connected  mostly  with  stratified  deposits,  of  a 
shaly,  sandstone,  or  conglomerate  character,  and  their  intersections 


122  DESCRIPTIONS   OF   MINERALS. 

with  porphyries.  The  chlorides  and  native  amalgams  are  found  in 
regions  more  toward  the  coast,  while  the  sulphides  and  ontlmonial 
ores  abound  nearer  the  Cordilleras.  The  richest  mines  are  not  far  dis- 
tant from  Copiapo,  in  the  mountains  north  of  the  valley  of  Huasco. 
The  mines  of  Mt.  Chanaryillo,  about  16  leagues  south  of  Copiapo, 
abound  in  horn  silver,  and  begin  to  yield  arsenic-sulphides  at  a  depth 
of  about  500  feet.  The  mines  of  Punta  Brava,  which  are  nearer  the 
Cordilleras,  afford  the  arsenical  and  antiinonial  orec. 

In  Peru,  the  principal  mines  are  in  the  districts  of  Pasco,  Chota,  and 
Huantaya.  Those  of  Pasco  are  15,700  feet  above  the  sea,  while  those 
of  Huantaya  are  in  a  low  desert  plain,  near  the  port  of  Yquique,  in  the 
southern  part  of  Peru.  The  ores  afforded  are  the  same  as  in  Chili. 
The  mines  of  Huantaya  are  noted  for  the  large  masses  of  native  silver 
they  have  afforded.  Silver  is  obtained  in  Peru,  also,  in  the  districts  of 
Caxamarca,  Pataz,  Huamanchuco,  and  Hualgayoc. 

The  Potosi  mines  in  Bolivia,  occur  in  a  mountain  of  argillaceous 
shale,  whose  summit  is  covered  by  a  bed  of  argillaceous  porphyry. 
The  ore  is  the  ruby  silver,  and  argentite  with  native  silver.  The  dis- 
trict of  Caracoles,  between  Chili  and  Bolivia,  yields  much  silver. 

In  Europe  the  principal  mines  are  those  of  Spain,  the  province  of 
Guadalajara,  where  the  ore  is  chiefly  freieslebenite  ;  of  Kongsberg  in 
Norway ;  of  Saxony,  chiefly  at  Freiberg  ;  the  Hartz  ;  in  Austria,  Hun- 
gary, Transylvania,  and  the  Banat  ;  and  Russia.  The  mines  of  Kongs- 
berg occur  in  gneiss  and  hornblende  slate,  in  a  gangue  of  calc  spar. 
They  were  especially  rich  in  native  silver. 

The  mines  of  Saxony  occur  mostly  in  gneiss,  in  the  vicinity  of  Frei- 
berg, Ehrenfriedensdorf,  Johanngeorgenstadt,  Annaberg,  and  Schnee- 

The  ores  of  the  Hartz  are  mostly  argentiferous  copper  pyrites  and 
galena,  yet  the  ruby  silver,  argentite,  stephanite,  occur,  especially  at 
Andreaskreutz,  and  the  mines  of  that  vicinity.  The  rock  intersected 
by  the  deposits  is  mostly  an  argillaceous  shale.  Calcitc  is  the  usual 
gangue,  though  it  is  sometimes  quartz. 

In  the  Tyrol,  Austria,  argentite,  argentiferous  tetrahedrite,  and  mis- 
pickel  occur  in  a  gangue  of  quartz,  in  argillaceous  schist.  The  Hun- 

farian  mines  at  Schemnitz  and  Kremnitz,  occur  in  syenyte  and  horn- 
lende  porphyry,  in  a  gangue  of  quartz,  often  with  calcite  or  barite 
(heavy  spar),  and  sometimes  fluorite.  The  ores  are  argentite.  tetrahe- 
drite, galena,  blende,  pyritous  copper  and  iron  ;  and  the  galena  and 
copper  ores  are  argentiferous.  France  produces  some  silver  from  ar- 
gent'rferous  galena  at  Huelgoet  in  Brittany,  and  the  mines  of  Pontgi- 
baud,  Puy-de-Dome. 

The  Russian  mines  are  in  Kolyvan  in  the  Altai,  and  Nertchinsk  in 
the  Daouria  Mountains,  Siberia  (east  of  Lake  Baikal).  The  Daouria 
mines  afford  an  argentiferous  galena  which  is  worked  for  its  silver  ; 
it  occurs  in  a  crystalline  limestone.  The  silver  ores  of  the  Altai  occur 
in  Silurian  schists  in  the  vicinity  of  porphyry,  which  contain  also 
gold,  copper,  and  lead  ores. 

The  mines  of  Mexico  are  most  abundant  between  18°  and  24°  north 
latitude,  on  the  back  or  sides  of  the  Cordilleras,  and  especially  the 
west  side  ;  and  the  principal  are  those  of  the  districts  of  Guanaxuato, 
Zacatecas,  Fresnillo,  Sombrerete,  Catorce,  Oaxaca,  Pachuca,  Real  del 
Monte,  Batopilas,  and  Tasco.  The  veins  traverse  very  different  rccka 


SILVER. 


123 


In  these  regions.  The  vein  of  Guanajuato,  the  most  productive  in 
Mexico,  intersects  argillaceous  and  chloritic  shale,  and  porphyry ;  it 
affords  one-forth  of  all  the  Mexican  silver.  The  Valeucian  mine  is 
the  richest  in  Guanaxuato.  The  Pachuca,  Real  del  Monte,  and  Moro 
districts,  are  near  one  another.  Four  great  parallel  veins  tranversv 
these  districts,  through  porphyry. 

In  the  United  States  the  chief  silver  mines  are  in  California,  Ne- 
vada, Colorado,  Utah,  Montana,  and  Idaho.  The  principal  California 
mines  are  in  its  southeastern  counties  bordering  on  Nevada,  namely : 
Alpine,  Mono,  and  Inyo  ;  the  total  yield  in  1874,  about  $1,700;000. 
Those  of  Nevada  are  the  Washoe  region,  about  Virginia  City  and  the 
Comstock  Lode  ;  in  Lander  County,  along  Reese  River  Valley,  etc., 
the  chief  town  of  which  is  Austin  ;  Esmeralda  County,  southeast  of 
Washoe  ;  in  Eureka  County,  next  east  of  Lander  ;  in  Lincoln  County, 
the  southeastern  of  the  State  ;  Huuiboldt  County  to  the  north  ;  White 
Pine,  Nye  and  Elko  counties,  east  and  southeast  of  Lander  County. 
The  rocks  connected  with  the  veins  in  Eastern  California  and  Western 
Nevada  are  eruptive  rocks,  related  for  the  most  part  to  andesyte  (in 
part,  named  propylite)  and  trachyte,  with  some  doleryte.  The  mines 
of  Utah,  are  those  of  the  Big  and  Little  Cottonwood  districts  (which 
include  the  Emma  Mine),  the  American  Fork  district,  the  Parley's 
'  Park  district  in  the  Wahsatch  Range  north  of  Big  Cottonwood,  and 
the  East  Tintic  district,  in  which  are  the  Eureka  Hill  mines  ;  those 
of  Arizona,  the  Heintzelman,  etc.;  of  Colorado,  in  the  San  Juan  region; 
of  Northern  Michigan,  at  the  copper  mines  ;  of  Canada,  at  Prince's 
Mine,  Spar  Island,  Lake  Superior. 

For  the  years  previous  to  1859  the  whole  yield  of  silver  from  United 
States  mines  is  estimated  at  $1,000,000.  The  following  are  the  amounts 
for  the  succeeding  years,  as  published  in  Jones's  Senate  Report  (1877), 
those  for  the  years  1871  to  1876,  inclusive,  being  from  estimates  by 
J.  J.Valentine. 


1859 $100,000 

1860 150,000 

1861 2,100,000 

1862 4,500,000 

1883 8,500,000 

1864 11,000,000 

18()5 11,250,000 

1866... 10,000,000 

1867 13,550,000 


1868 $12,000,000 

1869 13,000,000 

1870 17,3iO,000 

1871 19/286,000 

1872 19,924,429 

1873 27,483,302 

1874 29,699,122 

1875 31,635,239 

1876 39,292,924 


The  Comstock  Lode  contributed  to  the  silver  of  the  world  first  in  1861. 
In  1875  it  yielded  $14,492,350,  and  the  rest  of  Nevada  $6,717,636^ 
$21,209,983  ;  and  in  1876  these  amounts  were  20,570,078  and  7,462,752 
=$28,03 2,830.  The  $7,462,752  from  the  "  rest  of  Nevada"  in  1876, 
were  divided,  as  follows,  between  its  principal  mining  regions  :  Lan- 
der County,  Austin  district,  $1,187,500  ;  Esmeralda  County,  Columbus 
district,  $1,624,789  ;  Elko  County,  Cornucopia  district,  $460,048  ;  Eu- 
reka County,  $1,480,558  ;  Lincoln  County,  Pioche  or  Ely  district, 
$790,095  ;  Nye  County,  Tyboe  and  Reveille  districts,  $1,450,000. 

The  yield  in  1876  of  Utah  was  $3,351,5^0  ;  of  Colorado,  3,000,000  ; 
of  California,  1,800,000;  of  Arizona,  500,000;  of  Montana,  800,000; 
of  Idaho,  300,000  ;  of  New  Mexico,  400,000. 


124 


DESCRIPTIONS   OF   MINERALS. 


In  the  "  Elements  of  Metallurgy,"  of  J.  Arthur  Phillips,  the  yield 
for  1872  is  given  approximately,  as  follows  : 

Lbs.  Troy. 

52,400 
15,000 
92,000 


Great  Britain 

Norway  and  Sweden 

Hungary,  Transylvania,  and  the  Banat. 

Saxony 80,000) 

Haruz 27,500^ 

Rest  of  Germany 00,500) 

Russia 

France  

Italy 

Spain 

Peru 

Bolivia 

Chili , 

Central  America 

Mexico 

United  States. . 


178,000 

50,000 

16,500 

32,000 

100,000 

200,000 

450,000 

800,000 

53,000 

1,000,000 

1,250,000 


Total 3,788,900 

Mr.  Phillips  states  that  the  total  for  the  year  probably  amounted  to 
4,100,000  Ibs.  troy,  the  value  of  which  is  £13,000,000,  or  $03,000,000. 
In  the  above  the  amount  from  the  United  States  is  diminished  to  make 
it  correspond  with  the  preceding  statement  for  1872. 

The  following  table  gives,  in  dollars,  the  estimated  value  of  the 
World's  production  of  silver  in  recent  years  : 


Russia. 

United  States. 

Mexico  and 
South  America 

Other  Countries. 

1855 

600,000 

30,000,000 

10,000,000-40,600,000 

1800 
1865 
1870 
1875 

650,000 
700,000 
575,000 
500,000 

150,000 
11,250,000 
17,320,000 
31,635,000 

30,000,000 
30,000,000 
25,000,000 
25,000,000 

10,000,000=40,800,000 
10,000,000=51,950,000 
10,000,000=57,895,000 
10,000,000=67,135,000 

The  total  for  1876  is  estimated  at  76  millions. 

The  world's  production  of  silver  for  the  period  of  twenty-six  years, 
from  1852  to  1877,  is  estimated  at  $1,341,800,000  ;  for  the  preceding 
twenty-two  years— from  1830  to  1851,  inclusive— at  $600,400,000;  for 
the  preceding  thirty  years— from  1800  to  1830— at  $799,100,000. 


Native  Platinum. 

Isometric  :  but  crystals  seldom  observed.    Usually  in  flat- 
tened or  angular  grains  or  irregular  masses.    Cleavage  none. 
Color  and  streak  pale  or  dark  steel-gray.    Lustre  metallic, 


PLATINUM.  125 

shining.  Ductile  and  malleable.  H.=4-4-5.  G-.  =  16-19; 
17-108,  small  grains  ;  17-608,  a  mass.  Often  slightly  mag- 
netic, and  some  masses  will  take  up  iron  filings. 

Composition*  Platinum  is  usually  combined  with  more 
or  less  of  the  rare  metals  iridium,  rhodium,  palladium,  and 
osmium,  besides  copper  and  iron,  which  give  it  a  darker 
color  than  belongs  to  the  pure  metal,  and  increase  its  hard- 
ness. A  Russian  specimen  afforded,  Platinum  78-9,  iri- 
dium 5*0,  osmium  and  iridium  1-9,  rhodium  0-9,  palladium 
0-3,  copper  0-7,  iron  11-0=98'75. 

Platinum  is  soluble  in  heated  aqua  regia.  It  is  one  of  the 
most  infusible  substances  known,  being  wholly  unaltered 
before  the  blowpipe.  It  is  very  slightly  magnetic,  and  this 
quality  is  increased  by  the  iron  it  may  contain. 

Diff.  Platinum  is  at  once  distinguished  by  its  malleability 
and  extreme  inf visibility. 

Obs.  Platinum  was  first  detected  in  1735  in  grains  in 
the  alluvial  deposits  of  Choco  and  Barbac.oa  in  New  Granada 
(now  U.  States  of  Colombia),  within  two  miles  of  the  north- 
west coast  of  South  America,  where  it  received  the  name 
platina,  derived  from  the  word  plata,  meaning  silver.  Al- 
though before  known,  an  account  by  Ulloa,  a  Spanish 
traveler  in  America  in  1735,  directed  attention  in  Europe, 
in  1748,  to  the  metal.  It  is  now  obtained  in  Novita,  and 
at  Santa  Rita,  and  Santa  Lucia,  Brazil.  It  has  been  afforded 
most  abundantly  by  the  Urals.  It  occurs  also  on  Borneo  ;  in 
the  sands  of  the  Rhine ;  in  those  of  the  river  Jocky,  St. 
Domingo  ;  in  traces  in  the  United  States,  in  North  Carolina  ; 
at  La  Francois  Beaucc,  Canada  ;  and  with  gold  near  Point 
Orford,  on  the  coast  of  Northern  California  (probably  de- 
rived, according  to  W.  P.  Blake,  from  serpentine  rocks) ;  in 
British  Columbia. 

The  Ural  localities  of  Nischne  Tagilsk  and  Goroblagodat 
have  afforded  much  the  larger  part  of  the  platinum  of  com- 
merce. It  occurs,  as  elsewhere,  in  alluvial  beds  ;  but  the 
courses  of  platiniferous  alluvium  have  been  traced  to  a  great 
extent  up  Mount  La  Marti ane,  which  consists  of  crystalline 
rocks,  and  is  the  origin  of  the  detritus.  One  to  three  pounds 
are  procured  from  3,700  pounds  of  sand. 

Though  commonly  in  small  grains,  masses  of  considerable 
size  have  occasionally  been  found.  A  mass  weighing  1,088 
grains  was  brought  by  Humboldt  from  South  America  and 
deposited  in  the  Berlin  Museum.  Its  specific  gravity  was 


126  DESCRIPTIONS   OP   MINERALS. 

18-94.  In  the  year  1822,  a  mass  from  Condoto  was  de- 
posited in  the  Madrid  Museum,  measuring  2  inches  and  4 
lines  in  diameter,  and  weighing  11,641  grains.  A  more 
remarkable  specimen  was  found  in  the  year  1827  in  the 
Urals,  not  far  from  the  Demidoff  mines,  which  weighed  11£ 
(more  accurately,  11-57)  pounds  troy;  and  similar  masses 
are  now  not  uncommon.  The  largest  yet  discovered  weighed 
21  pounds  troy  ;  it  is  in  the  Demidoff  cabinet. 

Russia  affords  annually  about  35  cwt.  of  platinum,  which 
is  about  five  times  the  amount  from  Brazil,  Borneo,  Colom- 
bia, and  St.  Domingo.  Borneo  affords  about  500  pounds 
per  year. 

The  North  Carolina  platinum  was  found  with  gold  in 
Rutherford  County.  It  was  a  single  reniform  granule,  weigh- 
ing 2*54  grains.  Other  instances  are  reported  from  the 
Southern  gold  region. 

The  infusibility  of  platinum  and  its  resistance  to  the 
action  of  the  air,  and  moisture,  and  most  chemical  agents, 
renders  it  of  great  value  for  the  construction  of  chemical 
and  philosophical  apparatus.  The  large  stills  employed  in 
the  concentration  of  sulphuric  acid  are  now  made  of  plati- 
num ;  but  such  stills  are  gilt  within,  since  platinum  when 
unprotected  is  acted  upon  by  the  acid,  and  soon  becomes 
porous.  It  is  also  used  for  crucibles  and  capsules  in  chemi- 
cal anal}rsis  ;  for  galvanic  batteries  ;  as  foil,  or  worked  into 
cups  or  forceps,  for  supporting  objects  before  the  blowpipe. 
It  alloys  readily  when  heated  with  iron,  lead,  and  several  of 
the  metals,  and  is  also  attacked  by  caustic  potash  and  phos- 
phoric acid,  in  contact  with  carbon  ;  and  consequently  there 
should  be  caution  when  heating  it  not  to  expose  it  to  these 
agents. 

It  is  employed  for  coating  copper  and  brass ;  also  for 
painting  porcelain  and  giving  it  a  steel  lustre,  formerly 
highly  prized.  It  admits  of  being  drawn  into  wire  of  ex- 
treme tenuity. 

Platinum  was  formally  coined  in  Russia.  The  coins  had 
the  value  of  11  and  22  rubles  each. 

This  metal  fuses  readily  before  the  "compound  blow- 
pipe ; "  and  Dr.  Hare  succeeded  in  1837  in  melting  twenty- 
eight  ounces  into  one  mass.  The  metal  was  almost  as  malle- 
able and  as  good  for  working  as  that  obtained  by  the  other 
process;  it  had  a  specific  gravity  of  19-8.  He  afterwards 
succeeded  in  obtaining  from  the  ore  masses  which  were  90 


PALLADIUM.  127 

per  cent,  platinum,  and  as  malleable  as  the  metal  in  ordi- 
nary use,  though  somewhat  more  liable  to  tarnish,  owing  to 
some  of  its  impurities.  Deville  and  Debray  have  perfected 
this  process,  and  have  melted  over  25  pounds  of  platinum 
in  less  than  three-quarters  of  an  hour.  In  the  process  the 
osmium  present  is  oxidized  and  thus  removed. 

Platin-iridium.  Grains  of  iridium  have  been  obtained  at  Nischne 
Tagilsk,  consisting  of  76 '8  iridium,  and  19 '64  platinum,  with  some 
palladium  and  copper.  A  similar  platin-iridium  has  been  obtained  at 
Ava,  in  the  East  Indies.  Another,  from  Brazil,  contained  27 '8  iridium, 
55 '5  platinum,  and  6 '9  of  rhodium. 

Iridosmine.  A  compound  of  iridium  and  osmium  from  the  platinum 
mines  of  Eussia,  South  America,  the  East  Indies,  and  California.  The 
crystals  are  pale  steel-gray  hexagonal  prisms  ;  usually  in  flat  grains. 
H.  =  6  -7.  G.  =  19  -5-21 1.  Malleable  with  difficulty. 

The  composition  varies.  One  variety,  called  Newjanskite,  contains 
iridium  40 '8,  osmium  493,  rhodium  32,  iron  0'7.  Another,  Sisser- 
skite,  iridium  25*1,  osmium  74*9,  and  iridium  20,  osmium  80.  But 
analysis  affords  also  from  0'5  to  12  3  of  rhodium,  and  02  to  6 '4 
of  the  rarer  metal  ruthenium,  with  traces  usually  of  platinum,  cop- 
per and  iron.  The  grains  are  distinguished  by  their  superior  hardness 
from  those  of  platinum,  and  also  by  the  peculiar  odor  of  osmium  when 
heated  with  nitre.  Iridosmine  is  common  with  the  gold  of  Northern 
California,  and  injures  its  quality  for  jewelry.  Occurs  sparingly  in 
the  gold  washings  on  the  rivers  Du  Loup  and  Des  Plantes,  Canada. 

The  metal  iridium  is  extremely  hard,  and  is  used,  as  well  as  rho- 
dium, for  points  to  the  nibs  of  gold  pens.  Its  specific  gravity  is  21 '8. 

Laurite.  In  minute  octahedrons.  A  ruthenium  sulphide,  with  3 
per  cent,  of  osmium.  From  platinum  sands  of  Borneo  and  Oregon. 

Palladium. 

Isometric.  In  minute  octahedrons.  Occurs  mostly  in 
grains,  sometimes  composed  of  divergent  fibres.  Color 
steel-gray,  inclining  to  silver- white.  Ductile  and  malleable. 
H.  4-5-5.  G.  =11 -3-12 -2. 

Consists  of  palladium,  with  some  platinum  and  iridium. 
Fuses  with  sulphur,  but  not  alone. 

Obs.  Occurs  in  Brazil  with  gold,  and  is  distinguished 
from  platinum,  with  which  it  is  associated,  by  the  divergent 
structure  of  its  grains.  It  was  discovered  by  Wollaston,  in 
1803.  Selenpalladite,  or  Allopalladium,  is  native  palladium 
in  hexagonal  tables  from  Tilkerode  in  the  Hartz.  It  is  re- 
ported also  from  St.  Domingo  and  the  Urals.  Porpezile 
is  palladium  gold,  or  gold  containing  about  10  per  cent,  of 
palladium  ;  three  samples  assayed  at  the  Eio  de  Janeiro 
mint  yielding  11-1,  9 -75,  and  7 '7  per  cent,  of  palladium. 


128  DESCRIPTIONS   OF  MINERALS. 

This  metal  is  malleable,  and  when  polished  has  a  whitish 
steel-like  lustre  which  does  not  tarnish.  A  cup  weighing 
3J  pounds  was  made  by  M.  Breant  in^the  mint  at  Paris,  and 
is  now  in  the  garde-meuble  of  the  French  crown.  In  hard- 
ness it  is  equal  to  fine  steel.  1  part  fused  with  6  of  gold 
forms  a  white  alloy  ;  and  this  compound  was  employed,  at 
the  suggestion  of  Dr.  W^llaston,  for  the  graduated  part  of 
the  mural  circle  constructed  by  Trough  ton  for  the  Eoyal 
Observatory  at  Greenwich.  Palladium  has  been  employed 
also  for  certain  surgical  instruments. 

MERCURY. 

Mercury  occurs  native ;  alloyed  with  silver  forming  na- 
tive amalgam ;  and  in  combination  with  sulphur,  selenium, 
chlorine,  or  iodine,  and  with  sulphur  and  antimony  in  some 
tetrahedrite.  Its  ores  are  completely  volatile,  excepting 
when  silver  or  copper  is  present. 

Native  Mercury. 

Isometric.  Occurs  in  fluid  globules  scattered  through  the 
gangue.  Color  tin-white.  G.  — 13-56.  Becomes  solid  and 
crystallizes  at  a  temperature  of  —39°  F. 

Mercury,  or  quicksilver,  as  it  is  often  called  (a  translation 
of  the  old  name  "argentum  vivum),"  is  entirely  volatile 
before  the  blowpipe,  and  dissolves  readily  in  nitric  acid. 

Obs.  Native  mercury  is  a  rare  mineral,  yet  is  met  with 
at^the  different  mines  of  this  metal,  at  Almaden  in  Spain, 
Idria  in  Carniola  (Austria),  in  Hungary,  Peru,  and  in  Cali- 
fornia. It  is  usually  in  disseminated  globules,  but  is  some- 
times accumulated  in  cavities  so  as  to  be  dipped  up  in 
pails. 

Mercury  is  used  for  the  extraction  of  gold  and  silver  ores. 
It  is  also  employed  for  silvering  mirrors,  for  thermometers 
and  barometers,  and  for  various  purposes  connected  with 
medicine  and  the  arts. 

Native  Amalgam.     See  page  117. 

Cinnabar. — Mercury  Sulphide. 

Rhombohedral.  R^R=12°  3G'.  Cleavage  lateral,  high- 
ly perfect.  Crystals  often  tabular,  or  six-sided  prisms.  Also 
massive ;  sometimes  in  earthy  coatings. 


SILVER.  129 

Lustre  unmetallic,  of  crystals  adamantine ;  often  dull. 
Color  bright  red  to  brownish  red,  and  brownish  black. 
Streak  scarlet-red.  Sub  transparent  to  nearly  opaque.  H.  = 
2-2-5.  G.=  8-5-9.  Sectile. 

Composition.  Hg  S2  =  Sulphur  13-8,  mercury  86-2.  It 
often  contains  impurities.  The  liver  ore,  or  hepatic  cinna- 
bar, contains  some  carbon  and  clay,  and  has  a  brownish 
streak  and  color.  The  pure  variety  volatilizes  entirely  be- 
fore  the  blowpipe. 

Diff.  Distinguished  from  red  oxide  of  iron  and  chromate 
of  lead  by  vaporizing  before  the  blowpipe  ;  from  realgar  by 
giving  off  on  charcoal  no  alliaceous  fumes. 

Obs.  Cinnabar  is  the  ore  from  which  the  principal  part 
of  the  mercury  of  commerce  is  obtained.  It  is  when  pure 
identical  with  the  pigment  vermilion.  It  occurs  mostly  in 
connection  with  siliceous,  talcose  and  argillaceous  slates,  or 
other  stratified  deposits,  both  the  most  ancient  and  those  of 
more  recent  date.  The  mineral  is  too  volatile  to  be  expected 
in  any  abundance  in  proper  igneous  or  crystalline  rocks,  yet 
has  been  found  sparingly  in  granite. 

The  localities  are  mentioned  beyond. 

Metacinnabarite  is  the  same  compound  with  cinnabar,  but  differs  in 
crystallization  ;  it  is  from  Redington  Mine,  Lake  County,  California. 

Guadalcazarite,  of  Mexico,  is  Hg  S  in  which  a  little  of  the  sulphur 
is  replaced  by  selenium. 

Calomel  or  Horn  Quicksilver.  A  tough,  sectile  mercury  chloride,  of 
a  light  yellowish  or  grayish  color,  and  adamantine  lustre,  translucent 
or  subtranslucent,  crystallizing  in  secondaries  to  a  square  prism. 
H.=l-2.  G.=6'48.  It  contains  151  per  cent,  of  chlorine,  and  84 '9 
of  mercury. 

lodic  Mercury. .   A  reddish-brown  ore,  from  Mexico. 

Tiemannite.  A  dark  steel-gray  mercury  selenide,  from  the  Hartz, 
and  the  vicinity  of  Clear  Lake,  California. 

Coloradoite.  A  grayish  black  mercury  telluride,  with  G.=8'627, 
from  the  Keystone  and  Mountain  Lion  Mines,  Colorado.  (Genth.) 

Magnolite.  A  mercurous  tellurate,  Hg  0«  Te,  from  Magnolia  dis* 
trict,  Colorado. 

General  Remarks.— Tlie  following  are  the  regions  of  the  principal 
mines  of  mercury.  At  Idria,  in  Austria  (discovered  in  1407),  where 
the  ore  is  a  dark  bituminous  cinnabar  distributed  through  a  blackish 
shale  or  slate,  containing  some  native  mercury ;  at  Almaden,  in  Spain, 
near  the  frontier  of  Estremadura,  in  the  province  of  La  Mancha,  in 
argillaceous  beds  and  grit  rock,  which  are  intersected  by  dikes  of 
"  black  porphyry  "  and  granite — mines  mentioned  by  Pliny  as  afford- 
ing vermilion  to  the  Greeks,  700  years  before  the  Christian  era ;  in 
the  Palatinate  on  the  Rhine  ;  in  Hungary;  Sweden  ;  several  points  in 
France  ;  Ripa,  in  Tuscany ;  in  Shensi,  in  China ;  at  Arqueros,  % 


130 


DESCRIPTIONS    OF    MINERALS. 


Chili  •,  at  Huanca  Yelica  and  some  other  points  in  Peru  ;  at  St.  Onofre 
and  other  places  in  Mexico  ;  in  California  and  Idaho. 

The  most  noted  of  the  California  mines,  New  Almaden,  is  situated 
in  Mine  Hill,  Santa  Clara  County,  south  of  San  Francisco.  The  rocks 
are  altered  Cretaceous  slates,  talcose  in  part,  with  beds  of  serpentine 
either  side,  and  associated  also  with  beds  of  jasper  or  siliceous  slate. 
The  New  Idria  mine  is  in  Fresno  County,  in  the  Mt.  Diablo  Range,  and 
was  discovered  in  1855.  The  rocks  are  more  or  less  altered  silico- 
argillaceous  and  siliceous  slates  and  sandstones,  and  the  cinnabar  is 
distributed  irregularly  through  them  ;  between  this  and  the  Aurora 
Mine  on  San  Carlos  (the  highest  peak  of  the  Diablo  Range,  4,977  feet), 
there  is  much  serpentine  (in  which  is  chromic  iron)  and  siliceous  rock 
or  slate.  In  Napa  Valley,  Napa  County,  north  of  San  Francisco,  there 
are  other  valuable  mines  situated  in  rocks  closely  similar,  as  Whitney 
states,  to  those  affording  quicksilver  at  New  Almaden.  They  are  in 
a  serpentine  belt,  the  cinnabar  being  in  some  places  in  the  serpentine, 
but  mostly  in  the  peculiar  siliceous  rock  associated  with  it.  Native 
mercury  occurs  with  the  cinnabar. 

The  product  of  the  California  mines  of  mercury  in  1874,  is  given  as 
follows  by  Raymond,  in  his  "  Mineral  Resources  for  1875"  : 

New  Almaden Santa  Clara  County 9, 084  flasks. 


New  Idria  Fresno 

Cerro  Bonito " 

California Napa 

Manhattan. . 

Phoenix 

Washington. 

Redington Lake 

California  Borax. 
Great  Western . . 

Buckeye Colusa 

Missouri Sonoma 

Oakland ' ' 

Saint  John. .  ..Solano 


.7,000 
900 
,3,000 
,  620 
,  685 
.  200 
.7,200 
,  570 
1,900 
,  700 
,  200 
307 
1,900 


Which,  with  the  additions  from  a  few  other  less  productive  open- 
ings, make  a  total  of  34,254  flasks,  or  over  2,400,000  Ibs.  The  yield 
in  1867  was  44,386  flasks,  or  about  3,400,000  Ibs.  The  total  yield  of 
the  world  in  1872,  is  stated  by  Phillips  at  6,670,000  Ibs.  avoirdupois. 


COPPER. 


Copper  occurs  native  in  considerable  quantities  ;  and  also 
combined  with  oxygen,  sulphur,  selenium,  arsenic,  anti- 
mony, chlorine,  and  as  carbonate,  phosphate,  arsenate,  sul- 
phate, and  vanadate.  The  ores  of  copper  vary  in  specific 
gravity  from  3-5  to  8-5,  and  seldom  exceed  4  in  hardness. 


ORES   OF   COPPER.  13^ 

Native  Copper. 

Isometric.  In  octahedrons  ;  no  cleavage  apparent.  Often 
in  plates  or  masses,  or  arborescent  and  filiform  shapes. 

Color  copper-red.  Ductile  and  malleable.  H.  =2*5-3. 
G.=8-84. 

Native  copper  often  contains  a  little  silver  disseminated 
throughout  it.  Before  the  blowpipe  it  fuses  readily,  and  on 
cooling  it  is  covered  with  a  black  oxyd.  Dissolves  "in  nitric 
acid,  and  produces  a  deep  azure-blue  solution  on  the  addition 
of  ammonia. 

Obs.  Native  copper  accompanies  the  ores  of  copper,  and 
usually  occurs  in  the  vicinity  of  dikes  of  igneous  rocks. 

Siberia,  Cornwall,  and  Brazil  are  noted  for  the  native  cop- 
per they  have  produced.  A  mass,  supposed  to  be  from  Bahia, 
now  at  Lisbon,  weighs  2,616  pounds.  South  of  Lake  Supe- 
rior about  Portage  Lake  on  Keweenaw  Point,  and  also,  less 
abundantly,  on  the  Ontanagon  Eiver,  and  at  some  other 
points  in  that  region,  native  copper  occurs  mostly  in  veins 
in  trap,  and  also  in  the  enclosing  sandstone.  A  mass 
weighing  3,704  Ibs.  has  been  taken  from  thence  to  Wash- 
ington City  ;  it  is  the  same  that  was  figured  hy  School- 
craft,  in  the  American  Journal  of  Science,  volume  iii.,  p. 
201.  One  large  mass  was  quarried  out  in  the  ''  Cliff  Mine," 
whose  weight  has  been  estimated  at  200  tons.  It  was  40 
feet  long,  6  feet  deep,  and  averaged  6  inches  in  thickness. 
This  copper  contains,  intimately  mixed  with  it,  about  y\  per 
cent,  of  silver.  Besides  this,  perfectly  pure  silver,  in  strings, 
masses,  and  grains,  is  often  disseminated  through  the  cop- 
per, and  some  masses,  when  polished,  appear  sprinkled  with 
large  white  spots  of  silver,  resembling,  as  Dr.  Jackson  ob- 
serves, a  porphyry  with  its  feldspar  crystals.  Crystals  of 
native  copper  are  also  found  penetrating  masses  of  prehnite 
and  analcite  in  the  trap  rock.  This  mixture  of  copper  and 
silver  cannot  be  imitated  by  art,  as  the  two  metals  form  an 
alloy  when  melted  together.  It  is  probable  that  the  separa- 
tion in  the  rocks  is  due  to  the  cooling  from  fusion  being 
so  extremely  gradual  as  to  allow  the  two  metals  to  solidify 
separately,  at  their  respective  temperatures  of  solidification — 
the  trap  being  an  igneous  rock,  and  ages  often  elapsing,  as 
is  well  known,  during  the  cooling  of  a  bed  of  lava,  covered 
from  the  air.  Native  copper  occurs  sparingly  in  St.  Ignace 
and  Michipicoton  Islands,  Lake  Superior. 


132  DESCRIPTIONS   OF   MINERALS. 

Small  specimens  of  native  copper  hare  been  found  in  the 
States  of  New  Jersey,  Connecticut,  and  Massachusetts,  where 
the  Triassic  formation  occurs.  One  mass  from  near  Somer- 
yille,  N.  J.,  weighs  78  pounds,  and  is  said  originally  to  have 
weighed  128  pounds.  Within  a  few  miles  to  the  north  of 
New  Haven,  Conn.,  one  mass  of  90  pounds,  and  another  of 
200,  besides  other  smaller,  have  been  found  in  the  drift,  all 
of  which  came  from  veins  in  the  trap  or  associated  Triassic 
sandstone.  Near  New  Brunswick,  N.  J.,  a  vein  or  sheet  of 
copper,  from  a  sixteenth  to  an  eighth  of  an  inch  thick,  has 
been  observed  and  traced  along  for  several  rods. 

Native  copper  occurs  also  in  South  Australia  ;  it  is  stated 
that  a  single  train  from  the  Moonta  Mine  carried  away  at 
one  time  forty  tons  of  native  copper. 

Chalcocite. — Copper  Glance.    Vitreous  Copper  Ore.    Redrutliite. 

Trimetric.  /:  7=119°  35',  Cleavage 
parallel  to  /,  but  indistinct.  Also  in  com- 
pound crystals  like  aragonite.  Often  mas- 
sive. 

Color  and  streak  blackish  lead-gray  ;  often 
tarnished  blue  or  green.  Streak  sometimes 
shining.  H.=2'5-3.  G.  =5-5-5  -8. 

Composition.  Cu2  S— Sulphur  20-2,  cop- 
per 79-8=100.  B.B.  on  charcoal  gives  off 
fumes  of  sulphur,  fuses  easily  in  the  exte- 
rior flame  ;  and  after  the  sulphur  is  driven 
off,  a  globule  of  copper  remains.  Dissolves 
in  heated  nitric  acid,  with  a  precipitation  of  the  sulphur. 

Diff.  Resembles  argentite,  but  it  is  not  sectile,  like  that 
ore,  and  they  afford  different  results  before  the  blowpipe. 
The  solution  of  the  ore  in  nitric  acid  covers  an  iron  plate 
(or  knife  blade)  with  copper,  while  a  similar  solution  of  the 
silver  ore  covers  a  copper  plate  with  silver. 

Obs.  Occurs  with  other  copper  ores  in  beds  and  veins. 
At  Cornwall,  splendid  crystallizations  occur.  Siberia,  Hesse, 
Saxony,  the  Banat,  Chili,  etc.,  afford  this  ore. 

In  the  United  States,  a  vein  affording  fine  crystallizations 
occurs  at  Bristol,  Conn.  Other  localities  are  at  Wolcott- 
ville,  Simsbury,  and  Cheshire,  Conn.  ;  at  Schuyler's  Mines, 
and  elsewhere,  N.  J.  ;  in  the  U.  S.  copper-mine  district, 
Blue  Eidge,  Orange  County,  Virginia;  between  New  Market 
and  Taneytown,  Maryland ;  and  sparingly  at  the  copper 


ORES   OF   COPPER.  133 

mines  of  Michigan  and  the  Western  States;  also  at  some 
mines  north  of  Lake  Huron  ;  in  the  San  Juan  mining  region, 
Colorado ;  north  of  Gila  Riva,  near  the  borders  of  New 
Mexico  and  Arizona ;  at  the  Bruce  Mines,  Lake  Huron, 
and  at  Prince's  Mine,  Spar  Island,  and  on  Michipicoton 
Islands,  Lake  Superior. 

Covellite,  or  Blue  Copper.  A  dull  blue-black  massive  mineral,  with 
the  composition  CuS.  G=3'8.  It  contains  66*5  per  cent,  of  copper. 

Harrisite.  A  copper  glance  with  cubic  cleavage,  from  Canton  Mine, 
Ga. ;  probably  a  pseudomorph  after  galenite. 

Chalcopyrite.— Copper  Pyrites.    Copper-and-Iron  Sulphide. 

Dimetric.  Crystals  tetrahedral  or 
octahedral  ;  sometimes  compound. 
/  A  7=109°  53',  and  108°  40'.  Cleav- 
age indistinct.  Also  massive,  and  of 
various  imitative  shapes. 

Color  brass-yellow,  often  tarnished 
deep  yellow,  and  also  iridescent. 
Streak  unmetallic,  greenish  black,  and 
but  little  shining.  H.=3'5-4.  G. 
=4-15-4-3. 

Composition.     CuFe  S2  =  Sulphur 

34-9,  copper  34-6,  iron  30-5  =  100.  Fuses  B.B.  to  a  globule 
which  is  magnetic,  owing  to  the  iron  present.  Gives  sulphur 
fumes  on  charcoal.  With  soda  on  charcoal  affords  a  glo- 
bule of  metallic  iron  with  copper.  The  usual  effect  with 
nitric  acid. 

Diff.  This  ore  resembles  native  gold,  and  also  pyrite.  It 
is  distinguished  from  gold  by  crumbling  when  it  is  attempted 
to  cut  it,  kistead  of  separating  in  slices  ;  and  from  pyrite  in 
its  deeper  yellow  color,  and  in  yielding  easily  to  the  point  of 
a  knife,  instead  of  striking  fire  with  a  steel. 

Obs.  Copper  pyrites  occurs  in  veins  intersecting  gneiss 
and  other  rnetamorphic  rocks  ;  also  in  those  connected  with 
eruptive  rocks  ;  and  sometimes  in  cavities  or  veins  in  ordi- 
nary stratified  rocks.  It  is  usually  associated  with  pyrite, 
and  often  with  galenite,  blende,  and  copper  carbonates.  The 
copper  of  Fahlun,  Sweden,  is  obtained  mostly  from  this  ore, 
where  it  occurs  with  serpentine  in  gneiss.  Other  mines  of 
this  ore  are  in  the  Hartz,  near  Goslar  ;  in  the  Banat,  Hun- 
gary, Thuringia,  etc.  The  Cornwall  ore  is  mostly  of  this 
kind.  As  prepared  for  sale  at  Kedruth  it  rarely  yields  12 


134  DESCRIPTIONS   OP   MINERALS. 

per  cent.,  and  generally  only  7  or  8,  and  occasionally  as  little 
as  3  to  4  per  cent,  of  metal  ;  "6J  per  cent,  of  metal  may  be 
considered  an  average  of  the  produce  of  the  total  quantity  of 
ore  sold."  (Phillips,  1874.)  Such  poverty  of  ore  is  only  made 
up  by  its  facility  of  transport,  the  moderate  expense  of  fuel, 
or  the  convenience  of  smelting.  Its  richness  may  generally 
be  judged  of  from  the  color:  if  of  a  fine  yellow  hue,  and 
yielding  readily  to  the  hammer,  it  is  a  good  ore  ;  but  if  hard 
and  pale  yellow  it  contains  much  pyrite,  and  is  of  poor 
quality. 

In  the  United  States  there  are  many  localities  of  this  ore. 
It  occurs  in  mines  in  Vermont,  at  Strafford  ;  and  at  Shrews- 
bury, Corinth,  Waterbury  ;  also  in  New  Hampshire,  Maine, 
Massachusetts,  and  Connecticut;  in  New  York,  at  the  Ancram 
lead  mine  ;  also  near  Eossie,  and  at  Wurtzboro' ;  in  Penn- 
sylvania, at  Morgantown  ;  in  Virginia,  at  the  Phenix  copper 
mines,  Fauquier  County,  and  at  the  Walton  gold  mine, 
Luzerne  County;  in  Maryland,  in  the  vicinity  of  Liberty  and 
New  London  in  Frederick  County;  and  at  the  Patapsco 
mines  near  Sykesville  ;  in  North  Carolina,  in  Davidson  and 
Guilford  counties.  In  Michigan,  where  native  copper  is  so 
abundant,  this  is  a  rare  ore  ;  but  it  occurs  at  Presqu'isle,  at 
Mineral  Point,  and  in  Wisconsin,  where  it  is  the  predomi- 
nating ore  ;  in  Tennessee,  in  Polk  County,  at  the  Iliwassee 
mines ;  in  the  San  Juan  mining  region,  Colorado ;  in  Lan- 
der Co.,  and  elsewhere,  Nevada  ;  at  Copperopolis,  Calaveras 
Co.,  California  ;  also  at  the  Bruce  and  other  mines  on  Lake 
Huron  ;  and  Michipicoton  Islands,  in  Lake  Superior. 

Cubanite  is  a  copper-and-iron  sulphide,  containing  Sulphur  39 '0, 
iron  38'0,  copper  19 '8,  silica  2'3=99'12. 

Bornite. — Erubescite.    Variegated  Copper  Pyrites. 

Isometric.  Cleavage  octahedral  in  traces.  Occurs  in  oc- 
tahedrons and  dodecahedrons.  Also  massive. 

Color  between  copper-red  and  pinchbeck-brown.  Tar- 
nishes rapidly  on  exposure.  Streak  pale  grayish-black  and 
but  slightly  shining.  Brittle.  H.  =  3.  G.  =  5. 

Composition.  Cu3Fe  S3= Sulphur  28-6,  copper  55 -58,  iron 
16-36  ;  but  varies  much. 

The  ore  of  Bristol,  Conn.,  afforded  Sulphur  '25 '83,  copper 
61-79,  iron  11-77=99-39. 

B.B.  on  charcoal  fuses  to  a  brittle  globule  attractable  by 


ORES   OF   COPPER.  135 

» 

the  magnet  ;  dissolves  in  nitric  acid,  with  separation  of 
sulphur. 

I)  iff.  This  ore  is  distinguished  from  the  preceding  by  its 
pale  reddish-yellow  color,  and  its  rapidly  tarnishing  and 
becoming  of  bluish  and  reddish  shades  of  color,  the  quality 
to  which  the  name  erubescite,  from  the  Latin  word  for  to 
blush,  alludes. 

Obs.  Occurs,  with  other  copper  ores,  in  granitic  and  al- 
lied rocks,  and  also  in  stratified  formations.  The  mines  of 
Cornwall  have  afforded  crystallized  specimens,  and  it  is  there 
called,  from  its  color,  "  horse-flesh  ore."  Other  foreign 
localities  of  massive  varieties  are  Ross  Island,  Killarney,  Ire- 
laud  ;  Norway,  Hessia,  Silesia,  Siberia,  and  the  Banat. 

Fine  crystallizations  were  formerly  obtained  at  the  Bristol 
copper  mine,  Conn.,  in  granite;  and  also  in  red  sandstone, 
at  Cheshire,  in  the  same  State,  with  malachite  and  barite. 
Massive  varieties  occur  at  the  New  Jersey  mines,  and  in 
Pennsylvania. 

Orookesite.  A  copper  selenide,  containing  17 '25  per  cent,  of  thallium, 
and  a  little  silver. 

Domeykite,  Alyodonite  and  Whitneyite  are  copper  arsenides ;  Ber- 
zelianite,  a  copper  selenide  ;  Eucairite,  a  copper-and-silver  selenide. 

Tennantite.  A  compound  of  copper,  iron,  sulphur,  and  arsenic.  It 
occurs  in  dodecahedral  crystals,  brilliant,  with,  a  dark  lead-gray  color, 
and  reddish-gray  streak.  From  the  Cornish  mines  near  Redruth  and 
St.  Day  in  Cornwall. 

Tetrahedrite. — Gray  Copper.     Fahlerz. 

Isometric  and  tetrahedral.  Occurs  in  tetrahedral  forms. 
Cleavage  octahedral  in  traces. 

Color  between  steel-gray  and  iron- 
black.  Streak  nearly  like  the  color, 
sometimes  inclined  to  b"own  and 
cherry-red.  Rather  brittle.  H.=3- 
4-5.  G.  =4-5- 5-12. 

Composition.  Cus  S7  Sb2  (  =  4  Cu2 
S  +  Sb8  S3),  but  with  part  of  the  cop- 
per replaced  usually  by  iron  and 
zinc,  and  sometimes  silver  or  quick- 
silver, and  part  of  the  antimony  by 

arsenic,  and  rarely  bismuth.  It  'sometimes  contains  30  per 
cent,  of  silver  in  place  of  part  of  the  copper,  and  is  then 
called  argentiferous  tetrahedrite.  The  amount  of  arsenic 
varies  from  0  to  10  per  cent.  One  variety  from  Spain  in- 
cluded 10  per  cent,  of  platinum,  and  another  from  Hohen' 


136  DESCRIPTIONS   OF   MINERALS. 

• 

stein  some  gold.  Specimens  from  Schwatz,  and  some  oilier 
localities,  contain  15  to  18  per  cent,  of  mercury,  and  are 
called  ^/Huiio/i/c.  A  kind  containing  !)  (<>  i:>  percent,  of 
lead  and  10  to  13  of  silver,  has  been  called  MalinotrHkilc. 

Obs.  The  Cornish  mines,  Andnwibefg  in  the  llariz, 
Krcinnit?:  in  Hungary,  Freiberg  in  Saxony,  KapniU  in  Tran- 
sylvania, and  Dillenberg  in  Nassau,  alTord  line  crysialliza- 
tions  of  this  ore.  It  is  a  common  ore  in  the  Chilian  mines, 
and  it  is  worked  there  and  elsewhere  for  copper  and  often 
also  for  silver.  Occurs  also  in  Mexico  ;  in  Mariposa,  and 
Shasta  counties,  Cal. ;  abundantly  at  the  Sheba  and  De  Soto 
mines,  Ilumboldt  Co.;  Nevada,  near  Austin  in  Lander  Co.  ; 
in  the  San  Juan  region,  Colorado;  at  the  lleint/elman 
Mine,  and  the  Santa  Rita  Mine,  in  Ari/ona  ;  also  in  line 
crystallizations  in  the  caves  of  Huallanea,  on  the  Peruvian 
Andes,  at  a  height  of  about  14,700  feet,  an  ore  yielding 
much  silver. 

Bournonite,  Contains  Sulphur  29'f>,  antimony  05-0,  load  42*24,  cop- 
per 18*0  — 100.  Its  crystals  arc  modified  rectangular  prisms,  of  a  steel- 
gray  color  and  streak,  and  arc  often  compounded  into  shapes  like  a 
cog- wheel,  \\hence  it  is  called  trlu'.l-orc.  11.  =2 '5-3.  G.  —  5-700. 
Prom  the  Tyrol,  Hart/,  Transylvania,  Saxony,  Cornwall,  and  Siberia. 

Other  sulphautiiuonites  or  sulpharsenites  of  copper  are  (•/m/cdftihitc, 
Empl(t'tit<\  Itinnitc,  Stylotypite,  AiktHid',  timiryit^,  Polybasitc.  1'oly- 
basitc  contains  also  silver. 

Atacamite. — Copper  Oxichloride. 

Trimetrio ;  in  rhombic  prisms  and  other  forms ;  also 
granular  massive.  Color  green  to  blackish  green.  Lustre 
adamantine  to  vitreous.  Streak  apple-irreen.  Translucent 
to  subtranslucent.  II.  =  3-3-5.  G.  =  3-75-3-9.  Com- 
position, Cu  Clj  +  3  Cu  Oa  H8= Chlorine  1(1  •(»•!,  oxygen  11  '25, 
copper  11*25,  water  12-G6  =  iOO.  From  the  Atacama  ilesert, 
hdween  Chili  and  IVru.  and  clewhcre  in  Chili;  also  from 
Bolivia,  Vesuvius,  Saxony,  Spain,  Cornwall. 

' 
Cuprite. — Red  Copper  Ore. 

Isometric.  In  regular  octahedrons,  and  modified  forms  of 
the  same.  Cleavage  octahedral.  Also  massive,  and  some- 
times earthy. 

Color  dcevp  red,  of  various  shades.  Streak  brownish  red. 
Lustre  adamantine  or  submetallic  ;  also  earthy.  Subtrans- 
parent  to  nearly  opaque.  Brittle.  H.  =  3'5-4.  G.  =5*85- 
C-15. 


ORES   OF   COPPER. 


137 


Civ,  0  =  Oxygen  11*2,  copper  88'8.  B.B. 
on  charcoal,  yields  a  globule  of  copper.  Dissolves  in  nitric 
acid.  The  earthy  varieties  have  been  called  tile  ore,  from 
the  color. 

8. 


Diff.  From  cinnabar  it  differs  in  not  being  volatile  before 
the  blowpipe  ;  and  from  red  iron  ore  in  yielding  a  bead  of 
copper  on  charcoal,  and  copper  reactions. 

Obs.  Occurs  with  other  copper  ores  in  the  Banat,  Thu- 
ringia,  Cornwall,  at  Chessy  near  Lyons,  in  Siberia,  and  Bra- 
zil. The  octahedrons  are  often  green,  from  a  coating  of 
malachite. 

In  the  United  States,  it  has  been  observed  crystallized  and 
massive  at  Schuyler's,  Somerville,  and  the  Flemington  cop- 
per mines,  N.  J. ;  also  near  New  Brunswick,  N.  J. ;  at 
Bristol,  Conn.;  near  Ladenton,  Rockland  County,  N.  Y.;  in 
the  Lake  Superior  region. 

Tenorite,  Melaconite,  or  Black  Copper.  An  oxide  of  cop- 
per, CuO,  occurring  as  a  black  powder,  and  in  dull  black 
masses  and  botryoidal  concretions,  in  veins  or  along  with 
other  copper  ores ;  also  in  iron-gray  flexible  scales,  in  the 
Vesuvian  lavas.  It  is  an  abundant  ore  in  some  of  the  cop- 
per mines  of  the  Mississippi  Valley,  and  yields  GO  to  70  per 
cent,  of  copper.  It  results  from  the  decomposition  of  the 
sulphides  and  other  ores.  At  the  Hiwassee  Mine,  Polk  Co., 
Tennessee,  it  has  been  abundant.  It  was  formerly  found  of 
excellent  quality  in  the  Lake  Superior  copper  region. 

Chalcanthite.— Blue  Vitriol.     Sulphate  of  Copper. 

Triclinic.  In  oblique  rhomboidal  prisms.  Also  as  an 
efllorescence  or  incrustation,  and  stalactitic. 

Color  deep  sky-blue.  Streak  uncolored.  Subtransparcnt 
to  translucent.  Lustre  vitreous.  Soluble,  taste  nauseous 
and  metallic.  H.=2-2'5.  G.=2-21. 


138  DESCRIPTIONS  OF   MINERALS. 

Composition.  Cu  Ot  S  +  5  aq= Sulphuric  acid  (or  sulphur 
trioxide)  32'1,  copper  oxide  31*8,  water  36*1.  A  polished 
plate  of  iron  in  solutions  becomes  covered  with  copper. 

Obs.  Occurs  with  the  sulphides  of  copper  as  a  result  of 
their  decomposition,  and  is  often  in  solution  in  the  waters 
flowing  from  copper  mines.  Occurs  in  the  Hartz,  at  Fahlui\ 
in  Sweden,  and  in  many  other  foreign  copper  regions ;  in,( 
the  Hiwassee  copper  mine,  Tennessee ;  the  Canton  mine, 
Georgia  ;  at  Copiapo,  Chili. 

Blue  vitriol  is  much  used  in  dyeing  operations  and  in  the 
printing  of  cotton  and  linen ;  also  for  various  other  pur- 
poses in  the  arts.  It  has  been  employed  to  prevent  dry  rot, 
by  steeping  wood  in  its  solution  :  and  it  is  a  powerful  pre- 
servative of  animal  substances  ;  when  imbued  with  it  and 
dried,  they  remain  unaltered.  It  is  afforded  by  the  decom- 
position of  copper  pyrites,  in  the  same  manner  as  green  vit- 
riol from  iron  pyrites  ;  but  it  is  manufactured  for  the  arts, 
chiefly  from  old  sheathing-copper,  copper  turnings,  and  cop- 
per refinery  scales. 

In  Frederick  County,  Maryland,  blue  vitriol  is  made  from 
a  black  earth  which  is  an  impure  oxide  of  copper  with  cop- 
per pyrites. 

In  some  mines,  the  solution  of  sulphate  of  copper  is  so 
abundant  as  to  afford  considerable  copper,  which  is  obtained 
by  immersing  clean  iron  in  it,  and  is  called  copper  of  cemen- 
tation. At  the  copper  springs  of  Wicklow,  Ireland,  about 
500  tons  of  iron  were  laid  at  one  time  in  the  pits  ;  in  about 
12  months  the  bars  were  dissolved,  and  every  ton  of  iron 
yielded  a  ton  and  a  half,  and  sometimes  nearly  two  tons,  of 
a  precipitated  reddish  mud,  each  ton  of  which  produced  16 
cwt.  of  pure  copper.  The  Eio  Tinto  Mine  in  Spain  is  an- 
other instance  of  working  the  sulphate  in  solution.  These 
waters  yield  annually  1,800  cwt.  of  copper,  and  consume 
2,400  cwt.  of  iron. 

Brochantite.  An  insoluble  copper  sulphate,  containing  17 '7  per 
cent,  of  sulphur  trioxide.  Color  emerald-green.  In  tabular  rhombic 
crystals,  from  the  Urals,  Retzbanya,  Cornwall,  Mexico,  Chili,  Aus- 
tralia. Krisumgtie  and  Konigite  are  the  same  species. 

Langite,  CyanotricMte  (Velvet  copper  ore),  Kronkite,  Philippite, 
Enysite,  Linarite,  Dolerophanite,  Hydrocyanitc,  are  other  sulphates 
containing  copper,  the  last  two  anhydrous  ;  and  Gonnellite  is  another 
containing  chlorine,  from  Cornwall. 

The  Copper  tungstate,  Cuprotungstite,  occurs  of  a  yellowish-green 
color  in  Chili. 


g 
b 


ORES   OF    COPPER.  139 

Olivenite.  —  Hydrous  Copper  Arsenate. 

Trimetric.  /A/—  92°  30'.  In  prismatic  crystals,  and 
also  fibrous  and  granular  massive  .  Olive-green,  and  of 
other  greenish  shades,  to  liver  and  wood-brown.  Streak 
olive-green  to  brown.  Substransparent  to  opaque.  Brittle. 
H.  =  3.  G.=4-l-4-4. 

Composition.  Cu4  09  As2=  Arsenic  pentoxide  40-66,  copper 
oxide  56-15,  water  3;19  =  100.  Fuses  very  easily,  coloring 
the  flame  bluish  green.  B.B.  fuses  with  deflagration,  giv- 
ing off  arsenical  fumes,  and  affords  a  brittle  globule,  which 
with  soda  yields  metallic  copper. 

Obs.  From  Cornwall,  the  Tyrol,  Siberia,  Chili,  and  other 
places. 

Besides  the  above,  there  are  the  following  salts  of  copper  : 

Copper  Arsenate*.  —  Euchroite  has  a  bright  emerald  -green  color,  and 
contains  33  per  cent,  of  arsenic  acid,  and  48  of  oxide  of  copper  ;  occurs  in 
modified  rhombic  prisms  ;  H.=8*75  ;  G=8*4  ;  from  Libethen,  in  Hun- 
ary. Clinoclasite  (Aphancsite]  is  of  a  dark  verdigris-green  inclining  to 
lue,  and  also  dark  blue;  H.  =25-3;  G.  =4  19-4  '3(3.  It  contains  62'7  per 
cent,  of  copper  oxide  ;  from  Cornwall.  Erinite  has  an  emerald-green 
color,  and  occurs  in  mammillated  coatings  ;  H.=4'5-5  ;  G.=4'04;  con- 
tains 59  '4  per  cent,  of  copper  oxide  ;  from  Limerick,  Ireland.  Liroco- 
nite  varies  from  sky-blue  to  verdigris-green  ;  occurs  in  rhombic  prisms, 
sometimes  an  inch  broad  ;  H.=2-2'5;  G.=2-8-2'98.  Chalcophylliti 
(copper  mica}  is  remarkable  for  its  thin  foliated  or  mica-like  structure  • 
color  emerald  or  grass-green  ;  H.  =2  ;  G.  =2  '55.  Contains  58  per  cent. 
of  copper  oxide  ;  from  Cornwall  and  Hungary.  Tyrolite  (Copper 
froth)  is  another  arsenate  of  a  pale  apple-green  and  verdigris-green 
color  ;  it  has  a  perfect  cleavage  ;  it  contains  43  9  per  cent,  of  copper 
oxide  ;  from  Hungary,  Siberia,  the  Tyrol,  and  Derbyshire.  Cormcatt- 
iU  and  Cldorotile,  are  names  of  other  copper  arsenates.  These  dif- 
ferent arsenates  of  copper  give  an  alliaceous  odor  when  heated  on 
charcoal  before  the  blowpipe. 

Copper  Phosphates.  —  Pseudomalachite  (Phospliochalcite,  Ehlite,  Dt 
Ttydrite)  occurs  in  very  oblique  crystals,  or  massive  and  incrusting,  and 
has  an  emerald  or  blackish-green  color;  H.  =45-5  ;  G.  =4'34  ;  contains 
64  to  70  per  cent,  of  copper  oxide  ;  from  near  Bonn,  on  the  Rhine,  and 
also  from  Hungary.  Libethenite  has  a  dark  or  olive-green  color,  and 
occurs  in  crystals,  usually  octahedral  in  aspect,  and  massive  ;  H.  = 
4;  G.=3'6-8-8;  contains  66  '5  per  cent,  of  oxide  of  copper;  from 
Hungary  and  Cornwall.  Other  copper  phosphates  are  Veszelyite, 
Tagilite,  Isoclasite.  Torbernite  is  a  copper-and-uranium  phosphate. 
These  phosphates  give  no  fumes  before  the  blowpipe,  and  have  the 
reaction  of  phosphoric  acid. 

Copper  Vanadates.  —  Volborthite  is  a  copper-and-  calcium  vanadate 
from  the  Urals  ;  and  Mottrammite  and  Psittacinite,  copper-and-lead 
vanadates,  the  former  from  England,  and  the  latter  from  gold  mines 
in  Silver  Star  district,  Montana. 

Riwtite.     Yellowish-green  copper  antimonate  and  carbonate. 


140  DESCKIPTIONS   OP  MINERALS. 


Malachite. — Green  Copper  Carbonate. 

Monoclinic.  Usual  in  incrustations,  with  a  smooth  tube- 
rose, botryoidal,  or  stalactitic  surface  ;  structure  finely  and 
firmly  fibrous.  Also  earthy. 

Color  light  green,  streak  paler.  Usually  nearly  opaque  ; 
crystals  translucent.  Lustre  of  crystals  adamantine  inclin- 
ing to  vitreous ;  but  fibrous  incrustations  silky  on  a  cross 
fracture.  Earthy  varieties  dull.  H.=3'5-4.  G.=3'7-4. 

Composition.  Cu2  04  C  +  H2  0  =  Carbon  dioxide  (or  car- 
bonic acid)  19-9,  copper  oxide  71*9,  water  8*2=100.  Dis- 
solves with  effervescence  in  nitric  acid. 

B.B.  decrepitates  and  blackens,  colors  the  flame  green, 
and  becomes  partly  a  black  scoria.  AVith  borax  it  fuses  to  a 
deep-green  globule,  and  ultimately  affords  a  bead  of  copper. 

Diff.  Eeadily  distinguished  by  its  copper-green  color  and 
its  associations  with  copper  ores.  It  resembles  a  siliceous 
ore  of  copper,  chrysocolla,  a  common  ore  in  the  mines  of  the 
Mississippi  Valley;  hut  it  is  distinguished  by  its  complete  so- 
lution and  effervescence  in  nitric  acid.  The  color  also  is  not 
the  bluish  green  of  chrysocolla. 

Obs.  Green  malachite  usually  accompanies  other  ores  of 
copper,  and  forms  incrustations,  which,  when  thick,  have 
the  colors  banded  and  delicate  in  their  shades  and  blending. 
Perfect  crystals  are  quite  rare.  The  mines  of  Siberia,  at 
Nischne  Tagilsk,  have  afforded  great  quantities  of  this  ore. 
A  mass,  partly  disclosed,  measured  at  top  9  feet  by  18  ;  and 
the  portion  uncovered  contained  at  least  half  a  million 
pounds  of  pure  malachite.  Other  noted  foreign  localities 
are  Chessy,  in  France;  Sandlodge,  in  Shetland;  Schwatz 
in  the  Tyrol ;  Cornwall ;  the  Island  of  Cuba ;  Serro  do 
Bembe,  west  coast  of  Africa ;  copper  mines  of  Australia  ; 
Chili. 

The  copper  mine  of  Cheshire,  Conn.,  has  afforded  hand- 
some specimens  ;  also  Morgantown,  Perkiomen,  and  Phoenix- 
ville,  Penn.  ;  Schuyler's  Mine,  and  the  New  Brunswick 
copper  mine,  N.  J.  ;  it  occurs  also  in  Maryland,  between 
Newmarket  and  Taneytown  ;  and  in  the  Catoctin  Mountains ; 
in  the  Blue  Kidge,  Penn.,  near  Nicholson's  Gap  ;  also  in 

ntic  district,  Utah. 
TiAt  Mineral  Point,  Wisconsin,  a  bluish  silico-carbonate  of 
ocpper  occurs,  which  is  for  the  most  part  chrysocolla,  or  a 
mixture  of  this  mineral  with  the  carbonate. 


ORES   OF   COPPER.  141 

This  mineral  receives  a  high  polish  and  is  used  for  tables, 
mantelpieces,  vases  ;  and  also  ear-rings,  snuff-boxes,  and  va- 
rious ornamental  articles.  It  is  not  much  prized  in  jewelry. 
At  Versailles  there  is  a  room  furnished  with  tables,  vases, 
and  other  articles  of  this  kind  ;  and  similar  rooms  are  to  be 
found  in  many  European  palaces. 

Malachite  is  sometimes  passed  off  in  jewelry  as  turquois, 
though  easily  distinguished  by  its  shade  of  color  and  much 
inferior  hardness.  It  is  a  valuable  ore  when  abundant ;  but 
it  is  seldom  smelted  alone,  because  the  metal  is  liable  to  es- 
cape with  the  liberated  volatile  ingredient. 

Azurite.— Blue  Copper  Carbonate.     Blue  Malachite. 

Monoclinic.      In  modified  oblique   rhombic  prisms,  the 
crystals  rather  short   and  stout ; 
lateral  cleavage  perfect.  Also  mas- 
sive.    Often  earthy. 

Color  deep  blue,  azure  blue,  Ber- 
lin blue.  Transparent  to  nearly 
opaque.  Streak  bluish.  Lustre 
vitreous,  almost  adamantine.  Brit- 
tle. H.=3-5-4-5.  G.  =  3'5-3'85. 

Composition.  Cu3  07  C2  +  H2  0  = 
Carbon  dioxide  25 '6,  copper  oxide 
69*2,  water  5-2.  B.B.  and  in  acids  like  the  preceding. 

Obs.  Azurite  accompanies  other  ores  of  copper.  Chessy, 
France,  has  afforded  fine  crystals  ;  found  also  in  Siberia  ;  in 
the  Banat ;  near  Redruth  in  Cornwall ;  at  Phcenixville,  Pa., 
in  crystals  ;  in  Wisconsin  near  Mineral  Point ;  as  incrusta- 
tions, and  rarely  as  crystals,  near  Sing  Sing,  N.  Y. ;  near 
New  Brunswick,  N.  J. ;  near  Nicholson's  Gap,  in  the  Blue 
Ridge,  Pa. 

When  abundant  it  is  a  valuable  ore  of  copper.  It  makes 
a  poor  pigment  as  it  is  liable  to  turn  green. 

Aurichalcite  (Buratite)  is  a  hydrous  copper-and-zinc  carbonate,  or  a 
cuprous  hydrozincite,  pale  green  to  sky-blue  in  color  ;  from  the  Altai, 
Retzbanya,  Chessy  in  France,  Tyrol,  Spain,  Leadhills  in  Scotland,  and 
Lancaster,  Pa. 

Dioptase. — Copper  Silicate. 

Rhombohedral.  72 A  #  =  126°  24'.  Occurs  in  six-sided 
prisms  with  rhombohedral  terminations.  Color  emerald- 
green.  Lustre  vitreous.  Transparent  to  nearly  opaque. 
H.=5.  G.  =3-28-3 -35. 


142 


DESCRIPTIONS   OF   MINERALS. 


Composition.  CuII2  04  Si = Silica  38-1,  copper  oxide  50-4, 
water  11*5  =  100.  B.  B.  with  soda  on  charcoal  yields  copper, 
and  this,  with  its  hardness,  distinguishes  it  from  the  spe- 
cies it  resembles. 

Obs.  From  the  Khirgeez  Steppes  of  Siberia. 

Chrysocolla. — Hydrous  Copper  Silicate. 

Usually  as  incrustations  ;  botryoidal  and  massive.  Also 
in  thin  seams  and  stains ;  no  fibrous  or  granular  structure 
apparent,  nor  any  appearance  of  crystallization. 

Color  bright  green,  bluish  green.  Lustre  of  surface  of 
incrustations  smoothly  shining ;  also  earthy.  Translucent 
to  opaque.  H.  =  2-4.  G.  =  2-2  -4. 

Composition.  Cu03Si  +  2  aq= Silica  34*2,  copper  oxide 
45-3,  water  20-5=100'. 


NEW  JERSEY. 


Bowen. 

Beck. 

.   45.2 

42-6 

.  37-3 

40-0 

.  17-0 

16-0 

_ 

1-4 

SIBERIAN. 

Von  Kobell.  Berthier 

Oxide  of  copper. . .  40'0 55*1 

Silica 36-5 35 "4 

Water  20'2 28'5 

Carbonic  acid 2'1 

Oxide  of  iron 1-0 

The  mineral  varies  much  in  the  proportion  of  its  consti- 
tuents, as  it  is  not  crystallized. 

B.B.  it  blackens  in  the  inner  flame,  and  yields  water 
without  melting.  With  soda  on  charcoal  yields  a  globule 
of  copper. 

Diff.  Distinguished  from  green  malachite  as  stated  under 
that  species. 

Obs.  Accompanies  other  copper  ores  in  Cornwall,  Hun- 
gary, the  Tyrol,  Siberia,  Thuringia,  etc.  In  Chili  it  is 
abundant  at  the  various  mines.  In  Wisconsin  and  Missouri 
it  is  so  abundant  as  to  be  worked  for  copper.  It  was  for- 
merly taken  for  green  malachite.  It  also  occurs  at  the  Som- 
erville  and  Schuyler's  mines,  N.  J.,  at  Morgantown,  Penn., 
and  Wolcottville,  Conn. 

This  ore  in  the  pure  state  affords  30  per  cent,  of  copper  ; 
but  as  it  occurs  in  the  rock  will  hardly  yield  one-third  thia 
amount.  Still,  when  abundant,  as  it  appears  to  be  in  the 
Mississippi  Valley,  it  is  a  valuable  ore. 

General  EemarTcs. — The  most  valuable  sources  of  copper  for  the 
arts  are  native  copper,  chalcopyrite  or  "yellow  copper  ore,"  chalcocite 
or  "copper  glance,"  bornite  or  "variegated  copper  ore,"  malachite 


ORES   OF   COPPER.  143 

or  "  green  carbonate  of  copper,"  chrysocolla  or'  silicate,"  cuprite  or 
"red  oxide  of  copper  ;  "  and  occasionally  tenorite  or  "  black  copper." 

The  principal  copper  regions,  exclusive  of  the  American,  are  as 
follows.  The  Cornwall  and  Devon,  England,  where  the  ere  is  mostly 
chalcopyrite  ;  about  Mansfeld,  in  Prussia,  having  the  ore  distributed 
through  a  bed  of  red  shale  in  the  Permian  (Kupferschiefer),  about 
eighteen  inches  thick,  making  about  2^  per  cent,  of  the  bed  ;  the 
Urals  on  their  western  slope,  in  the  Permian,  as  in  Mansfeld  ;  also 
more  productively  on  the  eastern  side  of  the  Urals,  at  the  Nischne 
Tagilsk  and  Bogoslowskoi  mines,  in  Silurian  limestone  where  tra- 
versed by  eruptive  rocks,  and  at  the  Gumeschewskoi  mine,  in  argil- 
laceous shale,  the  ore  chiefly  malachite  and  cuprite  ;  in  France,  at 
Chessy,  near  Lyons,  of  malachite  and  azurite,  now  of  little  value  ;  in 
Norway,  at  Alten,  and  in  Sweden,  at  Fahlun  ;  in  Hungary,  at  Scheni- 
nitz,  Kremnitz,  Kapnik,  and  the  Banat  ;  in  Italy,  at  Monte  Catini  ;  in 
Spain,  in  the  province  of  Huelva,  where  is  the  Rio  Tinto  mine,  which 
affords  chalcopyrite,  and  also  the  sulphate  (p.  138) ;  in  Portugal,  at 
San  Domingo,  near  the  mouth  of  the  Guadiana  ;  in  Algeria,  Turkey, 
China,  Japan,  Cape  of  Good  Hope  ;  in  South  Australia,  where  are 
three  prominent  mines,  the  Burra,  Wallaroo,  and  Moonta,  their  yield 
in  1875,  £451,500  ;  New  South  Wales,  the  yield  in  1875,  about  6,000 
tons,  the  value  £508,800. 

In  South  America,  in  Chili,  in  the  vicinity  of  Copiapo,  and  less 
abundantly  at  other  places  to  the  south  ;  in  Bolivia,  also  in  Peru,  and 
the  Argentine  Republic,  but  not  much  developed.  In  Cuba,  but  much 
less  productive  than  formerly. 

In  Eastern  North  America,  some  copper  has  been  afforded  by  the 
^Triassic  of  New  Jersey  and  the  Connecticut  Valley,  but  there  are  no 
'producing  mines.  Corinth,  Vermont,  and  the  Hiwassee  mine,  Ten- 
nessee, are  worked.  The  chief  sources  of  copper  are  the  veins  of 
Northern  Michigan,  near  Lake  Superior.  The  veins  are  connected  with 
trap-dikes  intersecting  a  red  Lower  Silurian  sandstone  as  stated  on 
page  131.  The  first  discoveries  of  copper  ore  were  made  at  Copper 
Harbor.  Near  Fort  Wilkins  the  black  oxide  was  afterward  found  in  a 
large  deposit,  and  40,000  pounds  of  this  ore  were  shipped  to  Boston. 
On  further  exploration  in  the  trap,  the  Cliff  mine,  25  miles  to  the 
westward,  was  laid  open,  where  the  largest  masses  of  native  copper 
have  been  found,  and  which  still  proves  to  be  highly  productive. 
Other  veins  have  since  been  opened  in  various  parts  of  the  region,  at 
Eagle  Harbor,  Eagle  River,  Grand  Marais,  Lac  La  Belle,  Agate  Harbor, 
Torch  Lake,  on  the  Ontonagon,  in  the  Porcupine  Mountains,  and  else- 
where. The  country  north  of  Lakes  Superior  and  Huron,  IsLe  Royale 
and  the  Michipicotoii  Islands,  in  Lake  Superior,  also  afford  copper  ores, 
and  the  vicinity  of  Quebec  at  the  Acton  and  Harvey  Hill  mines,  in  rocks 
referred  to  the  Quebec  formation. 

In  Western  North  America,  in  Arizona,  there  are  large  veins  of 
copper  north  of  the  Gila,  on  the  borders  of  New  Mexico,  where  are 
the  Santa  Rita  and  Hanover  mines,  and  the  ores  are  cuprite,  chalco- 
cite,  malachite  ;  there  are  rich  veins  also  in  Colorado,  especially  in 
Gilpin  and  Park  counties,  in  Nevada,  and  California. 

The  amount  of  copper  produced  in  1872,  is  stated  as  follows  by 
J.  Arthur  Phillips  (Elements  of  Metallurgy)  : 


144  DESCRIPTIONS  OF  MINERALS. 

England 5,600  tons. 

Prussia 8,000 

Russia 6,500 

Hungary 3,500 

Sweden  and  Norway 2,500 

Spain 7,500 

Portugal 5,500 

Japan 1,000 

South  Australia 12,000 

South  Africa 7,500 

Chili  and  Bolivia 46,500 

United  States 12,600 

The  total  annual  production  is  estimated  by  Phillips  at  126,000  to 
130,000  tons. 

The  metal  copper  was  known  in  the  earliest  periods  and  was  used 
mostly  alloyed  with  tin,  forming  bronze.  The  mines  of  Nubia  and 
Ethiopia  are  believed  to  have  produced  a  great  part  of  the  copper  of 
the  early  Egyptians.  Eubsea  and  Cyprus  are  also  mentioned  as  afford- 
ing this  metal  to  the  Greeks.  It  was  employed  for  cutting  instru- 
ments and  weapons,  as  well  as  for  utensils  ;  and  bronze  chisels  are  at 
this  day  found  at  the  Egyptian  stone-quarries,  that  were  once  em- 
ployed in  quarrying.  This  bronze  (chalkos  of  the  Greeks,  and  ces  of 
the  Romans)  consisted  of  about  5  parts  of  copper  to  1  of  tin,  a  propor- 
tion which  produces  an  alloy  of  maximum  hardness.  Nearly  the 
same  material  was  used  in  early  times  over  Europe  ;  and  weapons  and 
tools  have  been  found  consisting  of  copper,  edged  with  iron,  indicating 
the  scarcity  of  the  latter  metal.  Similar  weapons  have  also  been 
found  in  Britain  ;  yet  it  is  certain  that  iron  and  steel  were  well  known 
to  the  Romans  and  later  Greeks,  and  to  some  extent  used  for  warlike" 
weapons  and  cutlery.  Bronze  is  hardened  by  hammering  or  pressure. 

Copper  knives,  axes,  chisels,  spear  heads,  bracelets,  etc. ,  have  been 
found  in  the  Indian  Mounds  of  Wisconsin,  Illinois,  and  the  neighbor- 
ing States  ;  and  there  is  evidence  that  the  Indians,  besides  using  drift 
masses  of  copper,  knew  of  the  copper  veins  of  Northern  Michigan,  and 
worked  them,  especially  in  the  Ontonagon  region,  where  their  tools 
and  excavations  have  been  discovered. 

Copper  at  the  present  day  is  very  various  in  its  applications  in  the 
arts.  It  is  largely  employed  for  utensils,  for  the  sheathing  of  ships, 
and  for  coinage.  Alloyed  with  zinc  it  constitutes  brass,  and  with  tin 
it  forms  bell-metal  as  well  as  bronze. 

Brass  consists  of  copper  65  per  cent.,  zinc  35  ;  with  53 '5  per  cent,  of 
zinc  the  alloy  is  silver- white ;  casting  'brass  of  65-72  copper,  35-28 
zinc  ;  or  molu  or  Dutch  metal,  of  70-85  copper,  15-25  zinc,  with  03  of 
each,  lead  and  tin  ;  brass  for  lathe-work  of  60-70  copper,  28-38  zinc,  2 
lead  ;  Muntz  metal,  for  the  sheathing  of  ships,  60  copper,  39  zinc, 
1  lead  ;  spelter  solder  for  brass,  copper  50,  zinc  50. 

Bronze  for  medals  consists  of  copper  93,  tin  7  ;  for  speculum  metal, 
copper  60,  tin  30,  arsenic  10  ;  for  casting  bronze,  copper  82-83,  tin  1-3, 
zinc  17-18  ;  for  gun-metal,  copper  85-92,  tin  8-15  ;  for  bell-metal, 
copper  65-80,  tin  20-35,  antimony  0-2  ;  antique  bronze,  copper  67-95, 
tin  8-15,  lead  0-1,  zinc  0-15. 

Lord  Rosse  used  for  the  speculum  of  his  great  telescope,  126  parts 


ORES    OF   LEAD. 


145 


of  copper  to  57|  parts  of  tin.  The  brothers  Keller,  celebrated  for 
their  statue  castings,  used  a  metal  consisting  of  91 '4  per  cent,  of  cop- 
per, 5 '53  of  zinc,  1/7  of  tin,  and  1/37  of  lead.  An  equestrian  statue  of 
Louis  XIV.,  21  feet  high,  and  weighing  53,263  French  pounds,  was 
cast  by  them  in  1699,  at  a  single  jet. 

An  alloy  of  copper  90,  and  aluminum  10,  is  sometimes  used  in  place 
of  bronze. 

LEAD. 

Lead  occurs  rarely  native  ;  generally  in  combination  with 
sulphur ;  also  rarely  with  arsenic,  tellurium,  selenium,  and 
in  the  condition  of  sulphate,  carbonate,  phosphate  and 
arsenate,  chromate  and  molybdate. 

The  ores  of  lead  vary  in  specific  gravity  from  5*5-8-2, 
They  are  soft,  the  hardness  of  the  species  with  metallic  lus- 
tre not  exceeding  3,  and  others  not  over  4.  They  are  easily 
fusible  before  the  blowpipe  (excepting  plumbo-resinite) ;  and 
with  soda  on  charcoal  (and  often  alone),  malleable  lead  may 
be  obtained.  The  lead  often  passes  olf  in  yellow  fumes, 
when  the  mineral  is  heated  on  charcoal  in  the  outer  flame, 
or  it  covers  the  charcoal  with  a  yellow  coating. 

Native  Lead. 

A  rare  mineral,  occurring  in  thin  laminae  or  globules, 
G.  =  11-35.  Said  to  have  been  seen  in  the  lava  of  Madeira  ; 
at  Alston  in  Cumberland  with  galena ;  in  the  County  of 
Kerry,  Ireland  ;  in  an  argillaceous  rock  at  Carthagena ;  at 
Camp  Creek,  Montana. 

Galenite. — Galena.     Lead  Sulphide. 

Isometric.  Cleavage  cubic,  eminent,  and  very  easily  ob- 
tained. Also  coarse  or  fine  granular  ;  rarely  fibrous. 

1. 


Color  and  streak  lead- gray.      Lustre  shining  metallic. 
Fragile.     H.=2-5.     G.  =  7'25-7-7. 


146  DESCRIPTIONS  OF   MINERALS. 

Composition.  PbS= Sulphur  13-4,  lead  86-6  =  100.  Often 
contains  some  silver  sulphide,  and  is  then  called  argentifer- 
ous galena  ;  and  at  times  zinc  sulphide  is  present.  The  ore 
of  veins  intersecting  crystalline  metamorphic  rocks  is  most 
likely  to  be  argentiferous.  The  proportion  of  silver  varies 
greatly.  In  Europe,  when  it  contains  only  7  or  8  ounces 
to  the  ton  it  is  worked  for  the  silver.  The  galenite  of  the 
Hartz  affords  -03  to  *05  per  cent,  of  silver  ;  the  English  '02 
to  -03  per  cent.  ;  that  of  Leadhills,  Scotland,  -03  to  -06  ; 
that  of  Pike's  Peak,  Colorado,  '05  to  -06;  that  of  Arkan- 
sas, -03  to  -05  ;  that  of  Middletown,  Ct.,  15  to  -20 ;  that  of 
Roxbury,  Ct.,  1*85  ;  that  of  Monroe,  Ct.,  3*0  ;  while  that  of 
Missouri  afforded  Dr.  Litton  only  '0012  to  "002?  per  cent, 
A  little  antimony  or  cadmium  is  sometimes  present. 

B.B.  on  charcoal,  it  decrepitates  unless  heated  with  cau- 
tion, and  fuses,  giving  off  sulphur,  coats  the  coal  yellow, 
and  finally  yields  a  globule  of  lead. 

Diff.  Galenite  resembles  some  silver  and  copper  ores  in 
color,  but  its  cubical  cleavage,  or  granular  structure  when 
massive,  will  usually  distinguish  it.  Its  reactions  before  the 
blowpipe  show  it  to  be  a  lead  ore,  and  a  sulphide. 

Obs.  Galena  occurs  in  granite,  limestone,  argillaceous 
and  sandstone  rocks,  and  is  often  associated  with  ores  of 
zinc,  silver  and  copper.  Quartz,  barite,  or  calcite  is  gener- 
ally the  gangue  of  the  ore ;  also  at  times  fluor  spar.  The 
rich  lead  mines  of  Derbyshire  and  the  northern  districts  of 
England,  occur  in  the  Subcarboniferous  limestone  ;  and  the 
same  rock  contains  the  valuable  deposits  of  Bleiberg,  in 
Austria,  and  the  neighboring  deposits  of  Carinthia.  The 
ore  of  Cornwall  is  in  true  veins  intersecting  slates  and  is 
argentiferous.  At  Freiberg  in  Saxony,  it  occupies  veins  in 
gneiss ;  in  the  Upper  Hartz,  and  at  Przibram  in  Bohemia, 
it  traverses  clay  slate,  of  Lower  Silurian  age  ;  at  Sahla, 
Sweden,  it  occurs  in  crystalline  limestone.  There  are  other 
valuable  beds  of  galena,  in  France  at  Poullaouen  and  Hue! 

§oet,  Brittany,  and  at  Villefort,  department  of  Lozere  ;  in 
pain  in  the  granite  and  argillyte  hills  of  Linares,  in  Cata 
Ionia,  Grenada,  and  elsewhere  ;  in  Savoy ;  in  Netherlands  a 
Yedrin,  not  far  from  Namur ;  in  Bohemia,  southwest  o 
Prague ;  in  Joachimstahl,  where  the  ore  is  worked  princi 
pally  for  its  silver ;  in  Siberia  in  the  Daouria  Mountains  in 
limestone,  argentiferous  and  worked  for  the  silver. 

The  deposits  of  this  ore  in  the  United  States  are  remark- 


ORES    OP   LEAD. 


ably  for  their  extent.  They  occur  in  limestone,  in  the  States 
of  Missouri,  Illinois,  Iowa,  and  Wisconsin  ;  argillaceous 
iron  ore,  pyrite,  calamine  and  smithsonite  ("dry  bone"  of 
the  miners),  blende  ("black-jack"),  carbonate  of  lead  or 
cerussite,  and  barite  or  heavy  spar,  are  the  most  common 
associated  minerals  ;  and  less  abundantly  occur  chalcopy- 
rite  and  malachite,  ores  of  copper  ;  also  occasionally  the 
lead  ores,  anglesite  and  pyromorphite  ;  and  in  the  Mine  La 
Motte  region,  black  cobalt,  and  linnaeite  an  ore  of  nickel. 

Lead  ore  was  first  noticed  in  Missouri  in  1700  and  1701. 
In  1720  the  mines  were  rediscovered  by  Francis  Renault  and 
M.  La  Motte  ;  and  the  La  Motte  bears  still  the  name  of  the 
latter.  Afterward  the  country  passed  into  the  hands  of 
Spaniards,  and  during  that  period,  in  1763,  a  valuable  mine 
was  opened  by  Francis  Burton,  since  called  Mine  a  Burton. 

The  lead  region  of  Wisconsin,  according  to  Dr.  D.  D. 
Owen,  comprises  62  townships  in  Wisconsin,  8  in  Iowa,  and 
10  in  Illinois,  being  87  miles  from  east  to  west,  and  54  miles 
from  north  to  south.  The  ore,  as  in  Missouri,  is  abundant, 
and  throughout  the  region  there  is  scarcely  a  square  mile 
in  which  traces  of  lead  may  not  be  found.  The  principal 
indications  in  the  eyes  of  miners,  as  stated  by  Mr.  Owen, 
are  the  following  :  fragments  of  calcite  in  the  soil,  unless 
very  abundant,  which  then  indicate  that  the  vein  is  wholly 
calcareous  or  nearly  so  ;  the  red  color  of  the  soil  on  the  sur- 
face, arising  from  the  ferruginous  clay  in  which  the  lead  is 
often  imbedded;  fragments  of  lead  ("gravel  mineral"), 
along  with  the  crumbling  magnesian  limestone,  and  den- 
dritic specks  distributed  over  the  rock;  also,  a  depression  of 
the  country,  or  an  elevation,  in  a  straight  line  ;  or  "  sink- 
holes ;  "  or  a  peculiarity  of  vegetation  in  a  linear  direction. 
The  ore,  according  to  Whitney,  occupies  chambers  or  open- 
ings in  the  limestone  instead  of  true  veins,  and  in  this 
respect  it  is  like  that  of  Derbyshire  and  Northern  England. 

The  mines  of  Wisconsin  and  Illinois  are  in  Lower  Silurian 
limestone  of  the  Trenton  period,  called  the  Galena  lime- 
stone ;  those  of  Southeastern  Missouri,  situated  chiefly  in 
Franklin,  Jefferson,  Washington,  St.  Frangois,  St.  Gene- 
vieve,  and  Madison  counties,  are  in  the  "  Third  Magnesian 
limestone  ;  "  also  Lower  Silurian,  but,  of  the  Calciferous  or 
Potsdam  period  ;  those  of  Southwestern  Missouri,  situated 
mostly  in  Newtown,  Jasper,  Lawrence,  Green  and  Dade 
counties,  and  in  the  western  part  of  McDonald,  Barry, 


DESCRIPTIONS   OF  MINERALS. 

Stone,  and  Christian  counties,  are  in  the  "  Keokuk  lime- 
stone," of  the  Subcarboniferous  period,  but  partly  in  Web- 
ster, Taney,  Christian,  and  Barry  counties,  in  the  Lower 
Silurian  "magnesian   limestone;"  those  of   Central  Mis- 
souri, situated  in  Moniteau,  Cole,  Miller,  Morgan,  and  other 
counties,  are  mostly  in   the   Lower   Silurian    "magnesian 
limestone,"  but  partly,  as  in  Northern  Moniteau,  in  the  Sub- 
carboniferous.     The  conditions  in  which  the  ore  occurs  in 
Missouri  confirms  the  opinion  of  Prof.  Whitney,  as  to  there 
being  no  true  veins.     Mr.  Adolf  Schmidt,  in  his  account  of 
the  Missouri  lead  ores,  says  that  the  deposits  contain  red 
clay,  broken  chert,  from  the  chert  bed,  and  portions  of  the 
limestone  beds,  along  with  the  lead  ;  that  the  barite  was  in 
troduced  after  the  lead  ;  that  some  caves  are  filled  througl 
all  their  ramifications,  while  others  arc  only  partly  fille  ~ 
and  he  adds  that  the  same  solvent  waters  that  made  the  caves 
and  horizontal  fissures  or  openings  may  have  held  the  vari 
ous  minerals  in  solution.     In  Derbyshire,  England,  the  de- 
posits contain  fossils  of  Permian  rocks,  showing  that,  al 
though  occurring  in  Subcarboniferous  limestone,  they  wen 
much  later  in  origin. 

Galenite  also  occurs  in  the  region  of  Chocolate  River  anc 
elsewhere,  Lake  Superior  copper  region  ;  on  Thunder  Bay 
and  Black  Bay  ;   at  Cave-in-Eock  in  Illinois,   along  with 
fluorite ;  in  New  York  at  Rossie,  St.  Lawrence  County,  in 
gneiss,  in  a  vein  3  to  4  feet  wide ;  near  Wurtzboro'  in  Sul- 
livan County,  a  large  vein  in  millstone  grit  ;  at  Ancram, 
Columbia  County  ;  Martinsburg,  Lewis  County,  N.  Y.,  and 
Lowville  ;  in  Maine,  at  Lubec  ;  also  of  less  interest  at  Blue 
Hill  Bay,  Birmingham  and  Parsonsfield ;  in  New  Hampshire, 
at  Eaton,  Bath,  Tamworth  and  Haverhill ;  in  Vermont,  at 
Thetford  ;  in  Massachusetts,  at  Southampton,  Leverett,  and 
Sterling,  but  without  promise  to  the  miner;  at  Newbury- 
port,  Mass.,  in  a  vein  which  is  now  worked  ;  at  Middletown, 
Ct.,  formerly  worked  as  a  silver-lead  mine  ;  in  Virginia,  i 
Wythe  County,  Louisa  County,   and  elsewhere  ;   in  Nort 
Carolina,  at  King's  Mine,  Davidson  County,  where  the  lea 
appears  to  be  abundant ;  in  Tennessee,  ab  Brown's  Creek 
and   at   Haysboro',   near    Nashville ;    in   Pennsylvania,    a 
Phcenixville  ;  in  Michipicoton  and  Spar  Islands,  Lake  Supe- 
rior.    In  Nevada  it  is  abundant  on  Watkins  River,  and  a 
Steamboat  Springs,  Galena  district ;  in  Colorado,  at  Pike's 
Peak,  etc.;  in  Arizona,  in  the  Patagonian  Mts.,  Santa  Rita 


ORES    OF   LEAD.  149 

Mts.,  and  in  Yuma  County;  in  the  Castle  Dome,  Eureka, 
and  other  districts,  where  the  ore  is  worked  for  the  silver  it 
contains. 

The  lead  of  commerce  is  obtained  from  this  ore.  It  is 
also  employed  in  glazing  common  stoneware  :  for  this  pur- 
pose it  is  ground  up  to  an  impalpable  powder  and  mixed  in 
water  with  clay ;  into  this  liquid  the  earthen  vessel  is  dipped 
and  then  baked. 

Lead  Selenides  and  Tellurides. 

These  various  ores  of  lead  are  distinguished  by  the  fumes  before  the 
blowpipe,  and  by  yielding,  on  charcoal,  ultimately,  a  globule  of  lead. 

Clausthalite,  or  lead  selenide,  has  a  lead-gray  color,  and  granular 
fracture,  and  is  occasionally  foliated.  H.=2'5-3.  G.  =7-6-8*8.  B.B.  on 
charcoal  a  horse-radish  odor  (that  of  selenium).  From  the  Hartz. 
There  is  a  lead  and  copper  selenide  (Zorgite)  which  has  the  sp.  gr. 
7-7 '5.  A  lead-and-mercury  selenide  (Lehrbachite)  occurs  in  foliated 
grains  or  masses  of  a  lead-gray  to  bluish  and  iron-black  color. 

Altaite,  or  lead  telluride.  A  tin- white  cleavable  mineral,  with  H.  =3 
-3'5,  and  G.  =816.  From  the  Altai  Mountains. 

Nagyagite,  or  Foliated  tellurium,  is  a  less  rare  species,  remarkable 
for  being  foliated  like  graphite  ;  color  and  streak  blackish  lead-gray  ; 
H.=1-1'5.  G.  =7-085.  It  contains  Tellurium  32*2,  lead  54'0,  gold  9'0, 
with  often  silver,  copper,  and  some  sulphur.  From  Transylvania. 

Antimonial  and  Arsenical  Sulphides  of  lead.  These  include  Sartorite, 
Zinkenite,  Plagionite,  Jamesonite,  Dufrenoysite,  Boulangerite,  Kobel- 
lite,  Meneghinite,  Geocronite  ;  also  Brongniardite  and  Freieslebenite, 
in  which  silver  is  also  present,  and  Stylotypite  and  Aikenite  in  which 
copper  is  also  present. 

Minium. — Oxide  of  Lead. 

Pulverulent.  Color  bright  red,  mixed  with  yellow.  Gr.  = 
4 '6.  Composition,  Pb3  04.  Affords  globules  of  lead  in  the 
reduction  flame  of  the  blowpipe. 

Obs.  Occurs  at  various  mines,  usually  associated  with 
galena,  and  is  found  abundantly  at  Austin's  Mines,  Wythe 
County,  Virginia,  with  white  lead  ore. 

Uses.  Minium  is  the  red  lead  of  commerce  ;  but  for  the 
arts  it  is  artificially  prepared. 

Plumbic  ochre  is  lead  protoxide,  of  a  yellow  color. 

Mendipite.  Color  white,  yel>3wish  or  reddish,  nearly  opaque.  Lustre 
pearly.  G.  =7-7-1.  PbCl2  +  Pb  0= Chloride  of  lead  38 '4,  lead  oxide 
61  6.  From  Mendip  Hills,  Somersetshire.  Cotunnite  is  a  chloride  of 
lead,  Pb  C12,  occurring  at  Vesuvius  in  white  acicular  crystals.  It  con- 
tains 74  -5  per  cent,  of  lead. 

Plumbogummite.  In  globular  forms,  having  a  lustre  somewhat 
like  gum  arable,  and  a  yellowish  or  reddish-brown  color.  H. =4-4*5. 


150  DESCRIPTIONS   OF   MINERALS. 

G.— 6*3-6*4.  Also  a  variety  4-4 -9.  Consists  of  lead,  alumina,  and 
water.  From  Huelgoet  in  Brittany,  and  at  a  lead  mine  in  Beaujeu  ; 
also  from  the  Missouri  mines,  with  black  cobalt,  and  from  Canton 
mine,  Ga. 

Anglesite. — Lead  Sulphate. 

Trimetric.  In  rhombic  prisms 
and  other  forms.  Lateral  cleavage. 
/A  7=  103°  43  £'.  Also  massive  ;  la- 
mellar or  granular. 

Color  white  or  slightly  gray  or 
green.  Lustre  adamantine  ;  some- 
times a  litte  resinous  or  vitreous. 
Transparent  to  nearly  opaque.  Brit- 
tle. H.  = .2-75-3.  G.  =  G  -1-6  -4. 

Composition.  Pb  0*  S,    affording 
about  73  per  cent,  of  oxide  of  lead. 
PHCENIXVILLE.  B.  B.  f uses  in  the  flame  of  a  candle, 

and,  on  charcoal,  yields  lead  with 
soda. 

Diff.  Resembles  aragonite  and  some  other  earthy  species ; 
but  this  and  the  other  ores  of  lead  are  at  once  distinguished 
by  specific  gravity,  and  also  by  their  yielding  lead  in  blow- 
pipe trials.  Differs  from  the  carbonate  of  lead  in  lustre 
and  in  not  dissolving  with  effervescence  in  acid. 

Obs.  Usually  associated  with  galena,  and  results  from  its 
decomposition.  Occurs  in  fine  crystals  at  Leadhills  and 
Wanlockhead,  Great  Britain,  and  also  at  other  foreign  lead 
mines.  In  the  United  States,  it  is  found  at  the  lead  mines 
of  Missouri  and  Wisconsin  ;  in  splendid  crystallizations  at 
Phoenixville,  Pa. ;  sparingly  at  the  Walton  gold  mine,  Louisa 
County,  Va. ;  at  Southampton,  Mass.;  in  Arizona,  and  in 
Cerro  Gordo,  Cal. 

Caledonite  is  a  lead-and-copper  sulphate,  of  azure-blue  color.  It  is 
remarkable  for  a  very  perfect  cleavage  in  one  direction.  G.=6'4 
From  Leadhills  and  Roughten  Gill,  England;  also  from  MinelaMotte, 
Missouri. 

Lead  selenate.  A  sulphur-yellow  mineral,  occurring  in  small  glob- 
ules, and  affording  before  the  blowpipe  on  charcoal  a  garlic  odor,  and 
finally  a  globule  of  lead.  It  is  named  Kerstenite. 

Crocoite. — Crocoisite.    Lead  Chromate. 

Monoclinic.     In  oblique  rhombic  prisms,   massive,  of  a 
bright  red  color  and  translucent.      Streak  orange-yellow. 
G.=5-9-6-l. 


ORES   OF   LEAD. 


Composition.  Pb  04  Cr= Chromium  trioxide  31-1,  lead 
oxide  68-9.  Blackens  and  fuses,  and  forms  a  shining  slag 
containing  globules  of  lead. 

Obs.  Occurs  in  gneiss  at  Beresof  in  Siberia,  and  also  in 
Brazil.  This  is  the  chrome  yellow  of  the  painters. 

Phcenicochroite  (or  Melanochroite)  is  another  lead  chromate,  contain- 
ing 23*0  of  chromium  trioxide,  and  having  a  dark  red  color ;  streak 
brick-red.  Crystals  usually  tabular  and  reticulately  arranged.  G.  =5'75. 
From  Siberia. 

Vauquelinite,  A  lead  and  copper  chromate,  of  a  very  dark  green 
or  pearly  black  color,  occurring  usually  in  minute  irregularly  aggre- 
gated crystals  ;  also  reniform  and  massive.  H.  =2-5-3.  G.  =5*5-5 '8. 
From  Siberia  and  Brazil  ;  also  at  the  lead  mine  near  Sing  Sing,  in 
mammillary  concretions. 

Stolzite,  or  lead  tungstatc.  In  square  octahedrons  or  prisms.  Color 
green,  gray,  brown,  or  red.  Lustre  resinous.  H.  =2*5-3.  G.— 7'9- 
81.  Contains  51  of  tungstic  acid  and  49  of  lead. 

Wulfenite,  or  lead  molybdate.  In  dull-yellow  octahedral  crystals, 
and  also  massive.  Lustre  resinous.  Contains  molybdenum  trioxide 
34*25,  protoxide  64 '43.  From  Bleiberg  and  elsewhere  in  Carinthia ; 
also  Hungary.  It  has  been  found  in  small  quantities  in  the  Southamp- 
ton lead  mine,  Mass. ,  and  in  fine  crystals,  at  Phcenixville,  Penn. 

Lead  SulpJialo-carbonates.  There  are  two  whitish  or  grayish  ores 
of  this  composition  called  Lanarkite  and  Leadhillite.  The  former  con- 
tains 71  per  cent,  of  carbonate  of  lead  ;  the  latter,  47. 

Pyromorphite. — Lead  Phosphate. 

Hexagonal.  In  hexagonal  prisms  ;  often 
in  crusts  made  of  crystals.  Also  in  globules 
or  reniform,  with  a  radiated  structure. 

Color  bright  green  to  brown  ;  sometimes 
fine  orange-yellow,  owing  to  an  intermix- 
ture with  cfiromate  of  lead.  Streak  white 
or  nearly  so.  Lustre  more  or  less  resinous. 
Nearly  transparent  to  subtranslucent.  Brit- 
tle. H.  =3-5-4.  G.  =  6-5-7 -1. 

Composition.  Pbs  08  P2  +  £  Pb  C12= Phos- 
phorus pentoxide  15 '71,  lead  oxide  82-27,  chlorine  2 -62 
=  100-60.  B.B.  fuses  easily  in  the  forceps,  coloring  the 
flame  bluish  green.  On  charcoal  fuses,  and  on  cooling, 
the  globule  becomes  angular  ;  the  coal  is  coated  white  from 
the  chloride,  and  nearer  the  assay,  yellow  from  lead  oxide. 
Soluble  in  nitric  acid. 

Diff.  Has  some  resemblance  to  beryl  and  apatite  ;  but  is 
quite  different  in  its  action  before  the  blowpipe,  and  much 
higher  in  specific  gravity. 


152  DESCRIPTIONS   OF   MINERALS. 

Obs.  Leadhills,  "Wanlockhead,  and  other  lead  mines  of 
Europe  are  foreign  localities.  In  the  United  States,  very 
handsome  crystallized  specimens  occur  at  King's  Mine,  in 
Davidson  County,  N.  C.  ;  other  localities  are  the  Perkiomen 
and  Phoenixville  mines,  Pa.  ;  the  Lubec  lead  mines,  Me.  ; 
Lenox,  N.  Y.  ;  formerly,  a  mile  south  of  Sing  Sing,  N.  Y. ; 
and  the  Southampton  lead  mine,  Mass. 

The  name  pyromorpMte  is  from  the  Greek  pur,  fire,  and 
morplie,  form,  alluding  to  its  crystallizing  on  cooling  from 
fusion  before  the  blowpipe. 

Mimetite.  A  lead  arsenate,  resembling  pyromorphite  in  crystalliza- 
tion, but  giving  a  garlic  odor  on  charcoal  before  the  blowpipe.  Color 
pale  yellow,  passing  into  brown.  H.  =2*75-3*5.  G.  =6*41.  Com- 
position, Pb3O8  As7  + 14  PbCl2= Arsenic  pentoxide  23*20,  lead  oxide 
74*96,  chlorine  2  *30 =100  '55.  From  Cornwall  and  elsewhere  ;  Phce- 
nixville,  Pa. 

Hedyphane  is  a  variety  of  mimetite  containing  much  lime.  It 
occurs  amorphous,  of  a  whitish  color,  and  adamantine  lustre.  H.  = 
3-5-4.  G.  =5-4-5 -5. 

Karyinite.  A  lead  arsenate  containing  manganese  and  calcium, 
from  Norway. 

Ecdemite.     A  lead  chloro-arsenate. 

Vanadinite.  A  lead  vanadate  occurring  in  hexagonal  prisms  like 
pyromorphite,  and  also  in  implanted  globules.  Color  yellow  to  red- 
dish brown.  H.  =2 -75-3.  G.  =6*6-7 '3.  From  Mexico;  also  from 
Wanlockhead  in  Dumfriesshire. 

Monimolite.     A  yellow  lead  antimonate. 

Nadorite.     A  yellow  lead  chlor-antimonate. 

Bindheimite.     A  hydrous  lead  antimonate. 

Cerussite. — White  Lead  Ore.     Lead  Carbonate. 

Trimetric.  In  modified  right  rhombic  prisms,  and  often 
in  compound  crystals,  two  or  three  crossing  one  another  as 

1.  2. 


in  fig.  2.     /A  1=117°  13'.     Also  in  six-sided  prisms  like 
aragonite.     Also  massive  ;  rarely  fibrous. 

Color  white,  grayish,  light  or  dark.     Lustre  adamantine. 
Brittle.     H.  =  3-3  -5.     G.  =  6  46-6  -48. 


LEAD.  153 

Composition.  Pb  03  0  =  Carbon  dioxide  16*5,  lead  oxide 
83-5  =  100.  B.B.  decrepitates,  fuses,  and  with  care  on  char- 
coal affords  a  globule  of  lead.  Effervesces  in  dilute  nitric 
acid. 

Diff.  Like  anglesite,  distinguished  from  most  of  the  spe- 
cies it  resembles  by  its  specific  gravity  and  yielding  lead 
when  heated.  From  anglesite  it  differs  in  giving  lead  alone 
before  the  blowpipe,  as  well  as  by  its  solution  and  efferves- 
cence with  nitric  acid,  and  its  less  glassy  lustre. 

Obs.  Associated  usually  with  galena.  Leadhills,  Wan- 
lockhead,  and  Cornwall  have  afforded  splendid  crystalliza- 
tions ;  also  Linares,  in  Spain,  and  other  lead  mines  on  the 
continent  of  Europe. 

In  the  United  States,  handsome  specimens  are  obtained 
at  Austin's  Mines,  Wythe  County,  Virginia,  and  at  King's 
Mine,  in  Davidson's  County,  North  Carolina ;  at  the  latter 
place  it  has  been  worked  for  lead,  and  it  is  associated  with 
native  silver  and  pyromorphite.  Perkiomen  and  Phoenix- 
ville,  Penn.,  afford  good  crystals.  It  occurs  also  at  "Vallee's 
Diggings,"  Jefferson  County,  Missouri,  and  other  mines,  in 
that  State ;  at  Brigham's  Mine,  near  the  Blue  Mounds, 
Wisconsin,  partly  in  stalactites ;  at  "  Deep  Diggings,"  in 
crystals ;  and  at  other  places,  both  massive  and  in  fine 
crystallizations. 

When  abundant,  this  ore  is  wrought  for  lead.  Large 
quantities  occur  about  the  mines  of  the  Mississippi  Valley. 
It  was  formerly  buried  up  in  the  rubbish  as  useless,  but  it 
has  since  been  collected  and  smelted.  It  is  an  exceedingly 
rich  ore,  affording  in  the  pure  state  75  per  cent,  of  lead. 

Carbonate  of  lead  is  the  "  white  lead  "  of  commerce,  so 
extensively  used  as  a  paint.  The  material  for  this  purpose 
is,  however,  artificially  made. 

Phosgenite  or  Corneous  Lead.  A  cliloro-earbonate  of  lead,  occurring 
in  whitish  adamantine  crystals.  H.=r2*75-4.  G.  =6-6  31.  Composi- 
tion, Pb03  C+PbCl3.  From  Derbyshire  and  Germany. 

Hydrocerussite.     Hydrous  lead  carbonate.     From  Sweden. 

Ganomal'te  is  a  white  lead-manganese  silicate,  affording  34  89  per 
cent,  of  lead  oxide.  From  Sweden.  Hyalotccite  is  a  lead-barium-lime 
silicate.  Both  are  from  Longban,  Sweden. 

General  Eemarks. — The  lead  of  commerce  is  derived  almost  wholly 
from  the  sulphide  of  lead  or  galenite,  the  localities  of  which  have 
already  been  mentioned.  In  some  mining  regions,  the  carbonate  and 
sulphate  are  abundant. 

The  lead  mines  of  the  Central  United  States  afforded  in  1826,  1,770 
tons  ;  iu  1842,  17,340  tons ;  and  of  late  years,  12,000  to  15,000  tons. 


154  DESCRIPTIONS   OF   MINERALS. 

Nevada  produced  10,000  tons  in  1870,  and  50,000  in  1875.  According 
to  Phillips,  England  produced  in  1872,  (50,450  tons  ;  Prussia,  in  1871, 
49,500  tons  ;  Spain,  in  1873,  102,600  tons  ;  France,  2,500  tons ;  Italy, 
15,500  tons  ;  Austria,  10,000  tons. 

ZINC. 

Zinc  occurs  in  combination  with  sulphur  and  oxygen ; 
and  also  in  the  condition  of  silicate,  carbonate,  sulphate, 
and  arsenate.  It  is  also  a  constituent  of  one  variety  of  the 
species  spinel.  The  chief  sources  of  the  metal  are  smith- 
sonite  or  the  carbonate ;  willemite  and  calamine,  or  sili- 
cates ;  zincite,  or  the  oxide ;  sphalerite  (blende),  or  the 
sulphide ;  and  franklinite. 

Sphalerite.— Blende.     Zinc  Sulphide. 

Isometric.  In  dodecahedrons,  octahedrons,  and  other  allied 
forms,  with  a  perfect  dodecahedral  cleavage.  Also  massive ; 


sometimes  fibrous.  Color  wax-yellow,  brownish-yellow,  to 
black,  sometimes  green,  red  and  white  ;  streak  white,  to  red- 
dish brown.  Lustre  resinous  or  waxy,  and  brilliant  on  a 
cleavage  face  ;  sometimes  submetallic.  Transparent  to  sub- 
translucent.  Brittle.  H.=3-5-4.  G.  =3  -9-4  '2.  Some 
specimens  become  electric  with  friction,  and  give  off  a  yel- 
low light  when  rubbed  with  a  feather. 

Composition.  ZnS  =  Sulphur  33,  zinc  67  =  100.  Contains 
frequently  a  portion  of  iron  sulphide  when  dark  colored  ; 
often  also  1  or  2  per  cent,  of  cadmium  sulphide,  especially 
the  red  variety.  Nearly  infusible  alone  and  with  borax. 
Dissolves  in  nitric  acid,  emitting  sulphuretted  hydrogen. 
Strongly  heated  on  charcoal  yields  fumes  of  zinc. 

Diff.  This  ore  is  characterized  by  its  waxy  lustre,  perfect 
cleavage,  and  its  being  nearly  infusible.  Some  dark  varieties 
look  a  little  like  tin  ore,  but  their  cleavage  and  inferior 
hardness  distinguish  them ;  and  some  clear  red  crystals, 


ZINC.  155 

which  resemble  garnet,  are  distinguished  by  the  same  char- 
aracters  and  also  by  their  very  difficult  fusibility. 

Obs.  Occurs  in  rocks  of  all  ages,  and  is  associated  gener- 
ally with  ores  of  lead ;  often  also  with  copper,  iron,  tin,  and 
silver  ores.  The  lead  mines  of  Missouri  and  Wisconsin  afford 
this  ore  abundantly.  Other  localities  are  in  Maine,  at  Lu- 
bec,  Bingham,  Dexter,  Parsonsfield  ;  in  New  Hampshire, 
at  Eaton,  Warren,  Haverhill,  Shelburne  ;  in  Vermont,  at 
Hatfield  ;  in  Connecticut,  in  Brooktield,  Berlin,  Roxbury, 
and  Monroe ;  in  New  York,  at  Ancram  lead  mine,  the 
Wurtzboro'  lead  vein,  at  Lockport,  Root,  2  miles  southeast 
of  Spraker's  Basin,  in  Fowler,  at  Clinton  ;  at  Franklin,  N. 
J.,  colorless  (Cleiophane)  ;  in  Pennsylvania,  at  the  Perkio- 
men  lead  mine  ;  in  Virginia,  at  Austin's  lead  mine,  Wythe 
County;  in  Tennessee,  near  Powell's  River,  and  at  Haysboro'; 
at  Prince's  Mine,  Spar  Island,  Lake  Superior,  with  ores  of  sil- 
ver ;  in  Beauce  Co.,  Canada,  where  it  is  slightly  auriferous. 

This  ore  is  the  Black-jack  of  miners. 

Blende  is  a  useful  ore  of  zinc,  though  more  difficult  of  re- 
duction than  calamine.  By  its  decomposition  (like  that  of 
pyrite),  it  affords  sulphate  of  zinc  or  white  vitriol. 

Wurtzlte  is  zinc  sulphide  in  hexagonal  crystals  from  Bolivia.  Huas- 
colite  and  Youngite  are  zinc-lead  sulphides. 

Zincite,— Red  Zinc  Ore.     Red  Zinc  Oxide. 

Hexagonal.  Usually  in  foliated  masses,  or  in  disseminated 
grains  ;  cleavage  eminent,  nearly  like  that  of  mica ;  but  the 
laminae  brittle,  and  not  so  easily  separable. 

Color  deep  or  bright  red  ;  streak  orange-yellow.  Lustre 
brilliant,  subadamantine.  Translucent  or  subtranslucent. 
H.  =4-4-5.  G.  =5-4-5 -7.  Thin  scales  by  transmitted  light 
deep  yellow. 

Composition.  Zn  0  =  Oxygen  19-7,  zinc  80-3  =  100.  B.B. 
infusible  alone,  but  yields  a  yellow  transparent  glass  with 
borax  ;  on  charcoal,  a  coating  of  zinc  oxide.  Dissolves  in 
nitric  acid  without  effervescence. 

Diff.  Resembles  red  stilbite,  but  distinguished  by  its  in- 
fusibility  and  also  by  its  mineral  associations. 

Obs.  Occurs  witli  franklinite  at  Mine  Hill  and  Sterling 
Hill,  Sussex  County,  N.  J. 

A  good  ore  of  zinc,  and  easily  reduced. 

Voltzite.  A  compound  of  sulphur,  oxygen  and  zinc,  4  Zn  S  +Zn  O. 
Occurs  in  implanted  globules  of  a  dirty  rose-red  color,  with  a  pearly 
lustre  on  a  cleavage  surface.  From  France,  and  near  Joachimstahl. 


156  DESCRIPTIONS    OP    MINERALS. 

Goslarite.— Sulphate  of  Zinc.     White  Vitriol. 

Trimetric.  Cleavage  perfect  in  one  direction.  /  A  /= 
90°  42'. 

Color  white.  Lustre  vitreous.  Easily  soluble  ;  taste  as- 
tringent, metallic,  and  nauseous.  Brittle.  H.  =2-2-5.  G.= 
1-9-2-1. 

Composition.  Zn04S  +  7  aq.  =Zinc  oxide  28-2,  sulphur 
trioxide  27*9,  water  43-9  =  100.  B.B.  gives  off  fumes  of 
zinc  on  charcoal,  which  cover  the  coal. 

Obs.  Eesults  from  the  decomposition  of  blende.  Occurs 
in  the  Hartz,  in  Hungary,  in  Sweden,  and  at  Holywell  in 
Wales. 

Sulphate  of  zinc  is  extensively  employed  in  medicine  and 
dyeing.  For  these  purposes  it  is  prepared  to  a  large  extent 
from  blende  by  decomposition,  though  this  affords,  owing  to 
its  impurities,  an  impure  sulphate.  It  is  also  obtained  by 
direct  combination  of  zinc  with  sulphuric  acid. 

White  Vitriol,  as  the  term  is  used  in  the  arts,  is  one  form 
of  sulphate  of  zinc,  made  by  melting  the  crystallized  sul- 
phate, and  agitating  till  it  cools  and  presents  an  appearance 
.like  loaf  sugar. 

Kottigite.  A  hydrous  zinc-cobalt  arsenate  of  reddish  color  (owing 
to  presence  of  cobalt)  from  Schneeberg 

Adamite.  A  hydrous  zinc-arsenate  of  honey -yellow  to  violet  color, 
from  Chili. 

Smithsonite. — Carbonate  of  Zinc. 

Ehombohedral.  R  A  72=107°  40'.  Cleavage  R  perfect. 
Massive  or  incrusting ;  reniform  and  stalactitic. 

Color  impure  white,  sometimes  green  or  brown ;  streak 
uncolored.  Lustre  vitreous  or  pearly.  Subtransparent  to 
translucent.  Brittle.  H.=5.  G.  =4-3-4-45. 

Composition.  Zn03C  =  Carbon  dioxide  35 -2,  zinc  oxide 
64-8  (four-fifths  of  which  is  pure  zinc)  =  100.  Often  con- 
tains some  cadmium.  B.B.  infusible  alone,  but  carbonic 
xicid  and  oxide  of  zinc  are  finally  vaporized.  Effervesces  in 
nitric  acid.  Negatively  electric  by  friction. 

Diff.  The  effervescence  with  acids  distinguishes  this 
mineral  from  the  following  species ;  and  the  hardness,  diffi- 
cult fusibility,  and  the  zinc  fumes  before  the  blowpipe,  from 
the  carbonate  of  lead  or  other  carbonates.  Besides,  the 
crystals  over  a  drusy  surface  terminate  usually  in  sharp 
three-sided  pyramids. 


ZINC.  157 

Obs.  Occurs  commonly  with  galena  or  blende,  and  usual- 
ly in  calcareous  rocks.  Found  in  Siberia,  Hungary,  Sile- 
sia ;  at  Bleiberg  in  Carinthia ;  near  Aix-la-Chapelle  in  the 
Lower  Rhine,  and  largely  in  Derbyshire  and  elsewhere  in 
England.  In  the  United  States,  it  is  abundant  at  Vallee's 
Diggings  in  Missouri,  and  at  other  lead  "  diggings"  in  Iowa 
and  Wisconsin  ;  also  in  Claiborne  County,  Tenn.  Sparingly 
also  at  Hamburg,  near  the  Franklin  Furnace,  N.  J. ;  at  the 
Perkiomen  lead  mine,  Pa.,  and  at  a  lead  mine  in  Lancaster 
County. 

Hydrozincite  is  a  hydrous  zinc  carbonate,  ZnO3  C+ 2  Zn02H,  of  a 
whitish  color,  with  G.=3'58-3'8. 

Aurichaldte  is  a  hydrous  carbonate  of  zinc  and  copper,  occurring  in 
drusy  incrustations  of  acicular  crystals,  having  a  pale  verdigris-green 
color.  From  Siberia,  Hungary,  England,  and  Lancaster,  Pa. 

Buratite  is  a  liine  aurichalcite. 

Willemite.— Zinc  Silicate.     Troostite. 

Ehombohedral.  R  A  72=116°  1'.  In  hexagonal  prisms, 
and  also  massive. 

Color  whitish,  greenish  yellow,  apple-green,  flesh-red,  yel- 
lowish brown.  Streak  uncolored.  Transparent  to  opaque. 
Brittle.  H.=:5-5,  G.=3-89-4-18. 

Composition.  Zn  03  Si  =  Silica  27*1,  zinc  oxide  72 '9  = 
100.  B.B.  fuses  with  difficulty  to  a  white  enamel ;  on  char- 
coal, and  most  easily  on  adding  soda,  yields  a  coating  which  is 
yellow  while  hot,  and  white  on  cooling,  and  which,  moistened 
with  cobalt  solution  and  treated  in  O.F.,  is  colored  bright 
green.  Gelatinizes  with  hydrochloric  acid. 

Obs.  From  Moresnet,  between  Liege  and  Aix-la-Chapelle ; 
Raibel  in  Carinthia ;  Greenland.  Abundant  at  both  Frank- 
lin and  Sterling,  mixed  with  zincite,  and  used  as  an  ore  of 
zinc  ;  also  in  prismatic  crystals  that  occasionally  are  six  inches 
long. 

Calamine. — Hydrous  Zinc  Silicate.     Galmei. 

Trimetric.  In  rhombic  prisms,  the  opposite  extremities 
with  unlike  planes.  /  A  /=104°  13'.  Cleavage  perfect 
parallel  to  /.  Also  massive  and  inerusting,  mammillated  or 
stalactitic. 

Color  whitish  or  white,  sometimes  bluish,  greenish,  or 
brownish.  Streak  uncolored.  Transparent  to  translucent. 
Lustre  vitreous  or  subpearly.  Brittle.  H.=4'5-5.  Gr.  =• 
3-16-3*9.  Pyro-electric. 


158  DESCRIPTIONS   OP   MINERALS. 

Composition.  Zn2  04  Si  +  aq.  =  Silica  25'0,  zinc  oxide  67'5, 
water  7'5  =  100. 

B.B.  alone  it  is  almost  infusible.  Forms  a  clear  glass 
with  borax.  In  heated  sulphuric  acid  it  dissolves,  and  the 
solution  gelatinizes  on  cooling. 

Diff.  Differs  from  calcite  and  aragonite  by  its  action  with 
acids  ;  from  a  salt  of  lead,  or  any  zeolite,  by  its  infusibility  ; 
from  chalcedony  by  its  inferior  hardness,  and  its  gelatiniz- 
ing with  heated  sulphuric  acid ;  and  from  smithsonite  by 
not  effervescing  with  acids,  and  by  the  rectangular  aspect  of 
its  crystals  over  a  drusy  surface. 

Obs.  Occurs  with  calamine.  In  the  United  States  it  is 
found  at  Vallee's  Diggings,  Mo.;  at  the  Perkiomen  and 
Pho3nixville  lead  mines ;  on  the  Susquehanna,  opposite 
Selinsgrove ;  at  Friedensville  in  Saucon  Valley,  two  miles 
from  Bethlehem,  Pa,,  with  massive  blende.  Abundantly  at 
Austin's  Mines,  Wythe  County,  Va.  Valuable  as  an  ore  of  zinc. 

Hopeite  is  a  rare  mineral  occurring  in  grayish-white  crystals  or  mas- 
sive, with  calamine,  and  supposed  to  be  a  hydrous  zinc-phosphate. 

Franklinite,  an  ore  of  iron,  manganese  and  zinc,  is  described  under 
iron,  on  page  179. 

General  Remarks. — The  metal  zinc  (spelter  of  commerce)  is  supposed 
to  have  been  unknown  in  the  metallic  state  to  the  Greeks  and  Romans. 
It  has  been  long  worked  in  China,  and  was  formerly  imported  in  large 
quantities  by  the  East  India  Company. 

The  principal  mining  regions  of  zinc  in  the  world  arc  in  Upper  Sile- 
sia, at  Tarnowitz  and  elsewhere  ;  in  Poland  ;  in  Carinthia,  at  Eaibel  and 
Bleiberg  ;  in  Netherlands  at  Llmberg  ;  at  Altenberg,  near  Aix-la- 
Chapelle  in  the  Prussian  province  of  the  Lower  Rhine  ;  in  England, 
in  Derbyshire,  Alstonmoor,  Mendip  Hills,  etc. ;  in  the  Altai  in  Eussia  ; 
besides  others  in  China,  of  which  little  is  known.  In  the  United 
States,  smithsonite  and  calamine  occur  with  the  lead  of  the  West  in 
large  quantities.  They  were  formerly  considered  worthless  and  thrown 
aside,  under  the  name  of  "  dry  bone."  In  Tennessee,  Claihorne 
County,  there  are  workable  mines  of  the  same  ores.  Calamine  occurs 
at  Friedensville,  Pennsylvania,  along  with  massive  blende  :  the  bed 
has  been,  but  is  not  now  worked.  The  zincite,  willemite,  and  frank- 
linite  of  Franklin,  New  Jersey,  are  together  worked  as  a  zinc  ore, 
and  both  zinc  and  zinc  oxide  are  produced.  Blende  is  sufficiently  abun- 
dant to  be  worked  at  the  Wurtzboro'  lead  mine,  Sullivan  County,  New 
York  ;  at  Eaton  and  Warren,  in  New  Hampshire  :  at  Lubec,  in  Maine  ; 
at  Austin's  Mine, Wythe  County,  Virginia,  and  at  some  of  the  Missouri 
lead  mines. 

The  amount  of  zinc  produced  in  1872,  in  Europe,  was  about  45,745 
tons  for  Belgium  ;  55,744  for  Germany  ;  3,000  for  Austria  :  15,000  for 
Great  Britain  ;  4,400  for  France  ;  4,400  for  Spain  :  making  the  total 
amount  128,289  tons.  In  the  United  States  the  amount  of  zinc  made 
in  1875  was  about  15,000  tons  ;  of  zinc  oxide,  8,500  tons. 


TIN.  159 

Zinc  is  a  brittle  metal,  but  admits  of  being  rolled  into  sheets  when 
heated  to  about  21 2°  F.  In  sheets  it  is  extensively  used  for  roofing 
and  other  purposes,  it  being  of  more  difficult  corrosion,  much  harder, 
and  also  very  much  lighter  than  lead.  It  is  also  employed  largely  for 
coating  (that  is,  making  what  is  called  galvariized)  iron.  Its  alloys  with 
copper  (page  144)  are  of  great  importance. 

The  white  oxide  of  zinc  is  much  used  for  white  paint,  in  place  of 
white  lead  ;  and  also  in  making  a  glass  for  optical  purposes. 

An  impure  oxide  of  zinc,  called  cadmia,  often  collects  in  large  quan- 
tities in  the  flues  of  iron  and  other  furnaces,  derived  from  ores  of  zinc 
mixed  with  the  ores  undergoing  reduction.  A  mass  weighing  600 
pounds  was  taken  from  a  furnace  at  Bennington,  Vt.  It  has  been  ob- 
served in  the  Salisbury  iron  furnace,  and  at  Ancram,  in  New  Jersey, 
where  it  was  formerly  called  Ancramite. 

CADMIUM. 

There  is  but  a  single  known  ore  of  this  rare  metal.  It  is 
a  sulphide,  and  is  called  Greenockite.  It  occurs  in  hexagonal 
prisms,  with  dissimilar  pyramidal  termination,  of  a  light 
yellow  color,  high  lustre,  and  nearly  transparent.  H.  =3- 
3-5.  G.  =4-8-5.  From  Bishopton,  Scotland. 

Cadmium  is  often  associated  with  zinc  in  sphalerite  and 
calamine.  The  cadmiferous  sphalerite  is  called  Przibramite. 

The  metal  cadmium  is  white  like  tin,  and  is  so  soft  that 
it  leaves  a  trace  upon  paper.  It  fuses  at  442°  F.  It  was 
discovered  by  Stromeyer  in  1818. 

TIN. 

Tin  has  been  reported  as  occurring  native  in  the  gold 
washings  of  the  Ural,  and  in  Bolivia.  There  are  two  ores, 
a  sulphide  and  an  oxide.  It  also  occurs  in  some  ores  of 
columbium,  tantalum,  and  tungsten. 

• 
Stannite.— Tin  Pyrites,  Sulphuret  of  Tin.     Tin  Sulphide. 

Commonly  massive,  or  in  grains.  Color  sfceel-gray  to  iron- 
black  ;  streak  blackish.  Brittle.  H.=4.  G.  =4-3-4 -6. 

Composition.  Sulphur  30,  tin  27,  copper  30,  iron  13  =  100. 

Obs.  From  Cornwall,  where  it  is  often  called  lell-metal 
ore?  from  its  frequent  bronze  appearance  ;  also  from  Ireland 
and  the  Erzgebirge. 


160 


DESCRIPTIONS   OF  "MINERALS. 


Cassiterite.— Tin  Ore.    Tin  Oxide. 


Dimetric. 
1. 


In  square  prisms  and  octahedrons;  often  com- 


2. 


pounded.   1  A  1  =  121°  40'  ;  1  i 

Al  i  (over  the   summit)  112° 

10',     (over    a    terminal   edge) 

133°  31'.     Cleavage  indistinct. 

Also  massive,  and  in  grains. 
Color  brown  or  black,  with  . 

a  high  adamantine  lustre  when 

in  crystals.     Streak  pale  gray 

to   brownish.       Nearly   trans- 
parent  to  opaque.     H.=6-7.     G.=  6-4-7-1. 

Composition.  Sn  02=  Oxygen  21*33,  tin  78-67  ;  often  con- 
tains a  little  iron,  and  sometimes  tantalum. 

B.B.  alone  infusible.     On  charcoal  with  soda,  affords  a 
-globule  of  tin. 

Stream  tin  is  the  gravel-like  ore  found  in  debris  in  low 
grounds.  Wood  tin  occurs  in  botryoidal  and  reniform  shapes 
with  a  concentric  and  radiated  structure  ;  and  toads-eye  tin 
is  the  same  on  a  small  scale. 

Diff.  Tin  ore  has  some  resemblance  to  a  dark  garnet,  to 
black  zinc  blende,  and  to  some  varieties  of  tourmaline.  It  is 
distinguished  by  its  infusibility,  and  its  yielding  tin  before 
the  blowpipe  on  charcoal  with  soda.  It  differs  from  blende 
also  in  its  superior  hardness. 

Obs.  Tin  ore  occurs  in  veins  in  the  crystalline  rocks, 
granite,  gneiss,  and  mica  slate,  associated  often  with  wolfram, 
copper  and  iron  pyrites,  topaz,  tourmaline,  mica  or  talc,  and 
albite.  Cornwall  is  one  of  its  most  productive  localities. 
It  is  also  worked  in  Saxony,  at  Altenberg,  Geyer,  Ehren- 
friedersdorf  and  Zinnwald;  in  Austria,  at  Schlackenwald  and 
other  places  ;  in  Malacca,  Pegu,  China,  and  especially  the 
Island  of  Banca  in  the  East  Indies ;  in  Queensland  and 
Northern  New  South  Wales,  Australia,  in  large  quantities ; 
in  Greenland.  It  occurs*  also  in  Galicia,  Spain  ;  at  Dale- 
carlia  in  Sweden  ;  in  Russia  ;  in  Mexico  at  Durango; 
and  Bolivia.  In  the  United  States  it  has  been  found  spar- 
ingly at  Chesterfield  and  Goshen,  Mass.;  in  some  of  the  Vir- 
ginia goldmines  ;  in  Lyme  and  Jackson,  N.  H.  ;  and  in  the 
Temescal  Range,  California. 

General  Remarks. — The  principal  tin  mines  now  worked,  are  those 
of  Cornwall,  Banca,  Malacca,  and  Australia. 
The  Cornwall  mines  were  worked  long  before  the  Christian  era. 


TIN.  161 

Herodotus,  450  years  before  Christ,  is  believed  to  allude  to  the  tin 
islands  of  Britain  under  the  cabalistic  name  Cassiterides,  derived  from 
the  Greek  kassiteros,  signifying  tin.  The  Phoenicians  are  allowed  to 
have  traded  with  Cornubia  (as  Cornwall  was  called,  it  is  supposed 
from  the  horn-like  shape  of  this  extremity  of  England).  The  Greeks 
residing  at  Marseilles  were  the  next  to  visit  Cornwall,  or  the  isles  ad- 
jacent, to  purchase  tin  ;  and  after  them  came  the  Romans,  whose 
merchants  were  long  foiled  in  their  attempts  to  discover  the  tin  market 
of  their  predecessors. 

Camdeu  says  :  "  It  is  plain  that  the  ancient  Britons  dealt  in  tin  mines 
from  the  testimony  of  Diodorus  Siculus,  who  lived  in  the  reign  of 
Augustus,  and  Timaus,  the  historian  in  Pliny,  who  tells  TIS  that  the 
Britons  fetched  tin  out  of  the  Isle  of  Icta  (the  Isle  of  Wight),  in  their 
little  wicker  boats  covered  with  leather.  The  import  of  the  passage 
in  Diodorus  is  that  the  Britons  who  lived  in  those  parts  dug  tin  out  of 
a  rocky  sort  of  ground,  and  carried  it  in  carts  at  low  water  to  certain 
neighboring  islands  ;  and  that  from  thence  the  merchants  first  trans- 
ported it  to  Gaul,  and  afterwards  on  horseback  in  thirty  days  to  the 
springs  of  Eridanus,  or  the  city  of  Narbona,  as  to  a  common  mart. 
JEthicus  too,  another  ancient  writer,  intimates  the  same  thing,  and 
adds  that  he  had  himself  given  directions  to  the  workmen."  In  the 
opinion  of  the  learned  author  of  the  Britannica  here  quoted,  and  others 
who  have  followed  him,  the  Saxons  seem  not  to  have  meddled  with 
the  mines,  or,  according  to  tradition,  to  have  employed  the  Saracens  ; 
for  the  inhabitants  of  Cornwall  to  this  day  call  a  mine  that  is  given 
over  working  Attal-Sarasin,  that  is,  the  leavings  of  the  Saracens. 

The  Cornwall  veins,  or  lodes,  mostly  run  east  and  west,  with  a  dip 
— hade,  in  the  provincial  dialect — varying  from  north  to  south  ;  yet 
they  are  very  irregular,  sometimes  crossing  each  other,  and  sometimes 
a  promising  vein  abruptly  narrows  or  disappears  ;  or  again  they  spread 
out  into  a  kind  of  bed  or  floor.  The  veins  are  considered  worth  work- 
ing when  but  three  inches  wide.  The  gangue  is  mostly  quartz,  with 
some  chlorite.  Much  of  the  tin  is  also  obtained  from  beds  of  loose 
stones  or  gravel  (called  sh'tdes^,  and  courses  of  such  gravel  or  tin  de- 
bris are  called  streams,  whence  the  name  stream  tin. 

The  Australian  mines  are  mainly  in  the  New  England  district  of 
Northern  New  South  Wales,  and  the  adjoining  part  of  Queensland,  and 
a  large  part  of  the  ore  goes  north  through  Queensland.  The  value  of 
the  tin  exported  in  1875  from  Queensland  was  £88,2*24,  and  from  New 
South  Wales  (Ann.  Rep.  Dept.  of  N.  S.  W.  Mines,  1876),  £561,311,  cor, 
responding  to  6,058  tons  of  tin  in  ingots,  besides  2,0?2  tons  of  ore. 
The  value  of  all  the  tin  raised  in  N.  S.  Wales,  prior  to  1875  is  £866,461. 
Beechwood,  Victoria,  also  affords  a  little  tin. 

The  annual  production  of  tin  in  1871  in  Great  Britain  was  11,320 
tons,  and  in  Banca  and  Malacca,  7,500. 

Tin  is  used  in  castings,  and  also  for  coating  other  metals,  especially 
iron  and  copper.  Copper  vessels  thus  coated  were  in  use  among  the 
Romans,  though  not  common.  Pliny  says  that  the  tinned  articles 
could  scarcely  be  distinguished  from  silver,  and  his  use  of  the  words 
incoquere  and  incoctilia  seems  to  imply,  as  a  writer  states,  that  the 
process  was  the  same  as  for  the  iron  wares  of  the  present  day,  by  im- 
mersing the  vessels  in  melted  tin.  Its  alloys  with  copper  are  mentioned 
on  page  144. 


162  DESCRIPTIONS   OF  MINERALS. 

Tin  is  also  used  extensively  as  tinfoil ;  but  most  tinfoil  consists  be* 
neath  the  surface  of  lead,  and  is  made  by  rolling  out  plates  of  lead  coated 
with  tin.  With  quicksilver  it  is  used  to  cover  glass  in  the  manufac- 
ture of  mirrors.  Tin  oxide  (dioxide),  obtained  by  chemical  processes, 
is  employed,  on  account  of  its  hardness,  in  making  a  paste  for  sharp- 
ening fine  cutting  instruments,  and  also  to  some  extent  in  the  prepara. 
tion  of  enamels.  The  chlorides  of  tin  are  important  in  the  precipita- 
tion of  many  colors  as  lakes,  and  in  fixing  and  changing  colors  in  dye- 
ing  and  calico-printing.  The  bisulphide  has  a  golden  lustre,  and  wa^ 
termed  aurum  musivum,  or  mosaic  gold,  by  the  alchemists.  It  ismucr 
used  for  ornamental  painting,  for  paper-hangings  and  other  purposes, 
under  the  name  of  bronze  powder. 

TITANIUM. 

Titanium  occurs  in  nature  combined  with  oxygen,  form- 
ing titanium  dioxide  or  titanic  acid,  and  also  in  oxygen  com- 
binations with  iron  and  calcium,  and  in  some  silicates.  It 
has  not  been  met  with  native. 

The  ores  are  infusible  alone  before  the  blowpipe,  or  nearly 
so.  Their  specific  gravity  is  between  3-0  and  4-5. 

Rutile. 

Dimetric.  In  prisms  of  four,  eight,  or  more  sides,  with 
pyramidal  terminations,  and  often  bent  as  in 
the  figure;  lAl  =  123°  7J'.  Crystals  often 
acicular,  and  penetrating  quartz.  Some- 
times massive.  Cleavage  lateral,  somewhat 
distinct. 

Color  reddish-brown  to  nearly  red  ;  streak 
very  pale  brown.      Lustre  submetallic-ada- 
mantine.     Transparent  to  opaque.     Brittle. 
H.  =6-6-5.     G.  =4-15-4 -25. 

Composition.  Ti  02  =  Oxygen  39,  titanium  61  =  100. 
Sometimes  contains  iron,  and  lias  nearly  a  black  color  ;  this 
variety  is  called  Nigrine.  B.B.  alone  unaltered  ;  with  salt 
of  phosphorus  a  colorless  bead,  which  in  the  reducing  flame 
becomes  violet  on  cooling. 

Diff.  The  peculiar  subdamantine  lustre  of  rutile,  and 
brownish-red  color,  much  lighter  red  in  splinters,  are  striking 
characters.  It  differs  from  tourmaline,  idocrase,  and  augite, 
by  being  unaltered  when  heated  alone  before  the  blowpipe  ; 
and  from  tin  ore,  in  not  affording  tin  with  soda  ;  from 
ephene  in  its  crystals. 


COBALT    AND   NICKEL.  163 

Obs.  Occurs  imbedded  in  granite,  gneiss,  mica  schist  sye- 
nyte,  and  in  granular  limestone.  Sometimes  associated  with 
hematite,  as  at  the  Grisons.  Yrieix  in  France,  Castile, 
Brazil,  and  Arendal  in  Norway,  are  some  of  the  foreign 
localities. 

In  the  United  States,  it  occurs  in  crystals  in  Maine,  at 
"Warren ;  in  New  Hampshire,  at  Lyme  and  Hanover ;  in 
Massachusetts,  at  Barre,  Windsor,  Shelburne,  Leyden,  Con- 
way  ;  in  Connecticut,  at  Monroe  and  Hunting-ton  ;  in  New 
York,  near  Edenville,  Warwick,  Amity,  at  Kingsbridge,  and 
in  Essex  County  at  Gouverneur  ;  in  Pennsylvania,  in  Chester 
County  ;  in  the  District  of  Columbia,  at  Georgetown  ;  in 
North  Carolina,  in  Buncombe  County  ;  in  Georgia,  in  Lin- 
coln and  Ilabersham  counties  ;  at  Magnet  Cove  in  Arkansas. 

The  specimens  of  limpid  quartz,  penetrated  by  long  aci- 
cular  crystals,  are  often  very  handsome  when  polished.  A  re- 
markable specimen  of  this  kind  was  obtained  in  Northern 
Vermont,  and  less  handsome  ones  are  not  uncommon  ;  they 
are  found  in  North  Carolina.  Polished  stones  of  this  kind 
are  c&Ned.  fleches  (T  amour  (love's  arrows)  by  the  French. 

This  ore  is  employed  in  painting  on  porcelain,  and  quite 
largely  for  giving  the  requisite  shade  of  color  and  enamel 
appearance  to  artificial  teeth. 

Octahedrite  (Anatase) ;  Brookite.  These  species  have  the  same  com- 
position as  rutile.  Octahedrite  occurs  in  slender  nearly  transparent 
octahedrons,  of  a  brown  color.  lAl=97°  51'.  H.  =  5'5-6.  G.=3'8- 
3-95.  From  Dauphiny,  the  Tyrol,  and  Brazil  ;  at  Smithfield,  R.  I. 

Brookite  is  met  with  in  thin  hair-brown  flat  trimetric  crystals,  at- 
tached by  one  edge.  Also  in  thick  iron-black  crystals,  as  in  the  va- 
riety called  Arkansite.  H.  —  5 '5-6.  From  Dauphiny;  Snowdon  in 
Wales  ;  Ellenville,  Ulster  County,  N.  Y.  ;  Paris,  Maine  ;  gold  wash- 
ings of  North  Carolina  ;  Magnet  Cove,  Arkansas  (Arkansite). 

Perofskite.  In  cubic  crystals,  of  yellow,  brown,  and  black  colors  ; 
chemical  formula  (Ti,  Ca)a  O3.  From  the  Urals,  the  Tyrol,  and  Magnet 
Cove,  Arkansas. 

Besides  the  ores  here  described,  titanium  is  an  essential  constituent 
also  of  ilmenite  (titanic  iron),  and  of  the  silicates  titanite  or  sphene 
(p.  290),  keilliauite  (p.  291),  wanoickite  ;  and  occurs  also  in  the  zir- 
conia  and  yttria  ores  ceschynite,  cerstcditc,  and  polymignite,  and  in  some 
other  rare  species  ;  sometimes  in  pyrochlore. 

COBALT,     NICKEL. 

Cobalt  has  not  been  found  native.  The  ores  of  cobalt 
are  sulphides,  arsenides,  arseno-sulphides,  an  oxide,  a  car- 
bonate, a  phosphate,  and  an  arsenate;  and  nickel  is  often 


164  DESCRIPTIONS  OP  MINERALS. 

associated  with  cobalt  in  the  sulphides  and  arsenides.  The 
ores  having  a  metallic  lustre  vary  in  specific  gravity  from 
6  -2  to  7  '2 ;  and  the  color  is  nearly  tin-white  or  pale  steel, 
gray,  inclined  to  copper-red.  The  ores  without  a  metallic 
lustre  have  a  clear  red  or  reddish  color,  and  specific  gravity 
of  nearly  3.  Cobalt  is  often  present  also  in  arsenopyrite  (or 
mispickel),  and  sometimes  in  pyrite. 

The  ores  of  nickel  are  sulphides,  arsenides,  arseno-sulph- 
ides,  and  anti mono-sulphides,  a  sulphate,  carbonate,  silicates, 
arsenate ;  and  the  metal  is  a  constituent  of  several  cobalt 
ores,  and  also  often  of  pyrrhotite  (magnetic  pyrites).  Specific 
gravity  between  3  and  8 ;  hardness  of  one  3,  but  mostly  be- 
tween 5  and  6.  Those  of  metallic  lustre  resemble  some  cobalt 
ores  ;  but  they  do  not  give  a  deep  blue  color  with  borax. 

Linnaeite.— Cobalt  Sulphide.     Cobalt  and  Nickel  Sulphide. 

Isometric.  In  octahedrons  and  cubo-octahedrons  ;  also 
massive.  Color  pale  steel-gray,  tarnishing  copper  red.  Streak 
blackish  gray.  H.  =  5  -5.  G.  =  4  -8-5. 

Composition.  Co3  S4  =  Sulphur  42  -0,  cobalt  5  -80  =  100  ;  but 
with  part  of  the  cobalt  replaced  by  nickel ;  copper  some- 
times present.  Siegenite  is  a  variety  containing  30  to  40  per 
cent,  of  nickel.  B.B.  on  charcoal  yields  sulphurous  odor 
and  a  magnetic  globule  ;  often  also  arsenical  fumes. 

Obs.  From  Sweden,  Prussia  ;  Mine  la  Motte  in  Missouri 
(Siegenite)  ;  Mineral  Hill  in  Maryland.  Sometimes  called 
cobalt  pyrites. 

Millerite.— Nickel  Sulphide.     Capillary  Pyrites. 

Ehombohedral.  Usually  in  capillary  or  needle-like  crys" 
tallizations  ;  sometimes  like  wool.  Also  in  columnar  crusts 
and  radiated.  Color  brass-yellow,  inclining  to  bronze-yellow, 
with  often  a  gray  iridescent  tarnish.  Streak  bright.  Brittle. 
H.=3-3-5.  G.  =4-6-5 -65. 

Composition.  Ni  S  =  Sulphur  35-6,  nickel  64-4=100.  In 
the  open  tube  sulphurous  fumes.  B.B.  on  charcoal  fuses 
to  a  globule ;  and  after  roasting,  gives,  with  borax  and  salt  of 
phosphorus,  a  violet  bead  in  O.F.,  which  in  K.F.  becomes 
gray  from  reduced  metallic  nickel. 


COBALT   AND   NICKEL.  165 

Obs.  From  Joachimstahl,  Przibram,  Kiechelsdorf  ;  Sax- 
ony ;  Cornwall  ;  at  the  Sterling  Mine,  Antwerp,  N.  Y.;  at 
the  Gap  Mine,  Lancaster  Co.,  Pa.;  at  St.  Louis,  Mo.,  in 
capillary  forms,  and  sometimes  wool-like,  in  cavities  in  mag- 
nesian  limestone.  A  valuable  ore  of  nickel. 

Beyrichite  has  the  formula  Ni5  S7. 

Smaltite.  —  Cobalt  Glance.     Chloanthite. 

Isometric.  Occurs  in  octahedrons,  cubes,  and  dodecahe- 
drons, and  other  forms.  See  figs.  1,  2,  3,  page  17,  and  17,  27, 
page  20.  Cleavage  octahedral,  somewhat  distinct.  Also 
reticulated  ;  often  massive. 

Color  tin-white,  sometimes  inclining  to  steel-gray.  Streak 
grayish  black.  Brittle.  Fracture  granular  and  uneven. 


Composition.  (Co,  Ni)  As2  ;  the  ore  being  either  a  cobalt 
arsenide,  or  cobalt-nickel  arsenide  ;  and  graduating  into  the 
nickel  arsenide  called  Chloanthite.  The  cobalt  in  the  ore 
may  constitute  23*5  per  cent.  ;  but  it  may  be  wholly  absent 
as  in  the  chloanthite.  In  addition,  iron  often  replaces  part 
of  the  other  metals,  as  in  the  variety  Safflorite. 

In  the  closed  tube  gives  a  sublimate  of  metallic  arsenic  ; 
in  the  open  tube  a  white  sublimate  of  arsenous  oxide,  and 
sometimes  traces  of  sulphurous  acid.  B.B.  on  charcoal, 
affords  an  arsenical  odor,  fuses  to  a  globule  which  gives  re- 
action for  iron,  cobalt,  and  nickel. 

Diff.  Arsenopyrite  (mispickel)  has  tho  white  color  of 
smaltite,  but  it  yields  sulphur  as  well  as  arsenic,  and  in  a 
closed  tube  affords  arsenic  sulphide,  orpiment  and  realgar. 

Obs.  Usually  in  veins  with  ores  of  cobalt,  silver,  and 
copper.  Occurs  in  Saxony,  especially  at  Schneeberg  ;  also 
in  Bohemia,  Hessia,  and  Cornwall. 

In  the  United  States  it  is  found  in  gneiss  with  copper 
nickel  (niccolite),  at  Chatham,  Conn. 

Cobaltite. 

Isometric.  Crystals  like  those  of  pyrite,  but  silver-white 
in  color  with  a  tinge  of  red,  or  inclined  to  steel-gray.  Streak 
grayish  black.  Brittle.  H.  =  5  -5.  G.  =  6  -63. 

Composition.  CoS2  +  Co  As2=  Co  AsS  =  Arsenic  45-2,  sul- 
phur 19-3,  cobalt  35-5  =  100,  but  often  with  much  iron 
and  occasionally  a  little  copper.  Unaltered  in  the  closed 


16(>  DESCRIPTIONS   OF   MINERALS. 

tube ;  but  in  the  open  tube,  yields  sulphurous  fumes  and  a 
white  sublimate  of  arsenous  oxide.  B.B.  on  charcoal  yields 
sulphur  and  arsenic  and  a  magnetic  globule ;  with  borax  a 
cobalt-blue  globule. 

Diff.  Unlike  smaltite  affords  sulphur,  and  has  a  reddish 
tinge  in  its  white  color. 

Obs.  From  Sweden,  Norway,  Siberia,  and  Cornwall. 
Most  abundant  in  the  mines  of  Wehna  in  Sweden,  first 
opened  in  1809. 

Niccolite.— Copper  Nickel.     Arsenical  Nickel. 

Hexagonal.  Usually  massive.  Color  pale  copper-red. 
Streak  pale  brownish-red.  Lustre  metallic.  Brittle.  H.  = 
5-5-5.  G.  =  7-3-7-7. 

Corn-position.  Ni  As— Nickel  44,  and  arsenic  56 ;  some- 
times part  of  the  arsenic  is  replaced  by  antimony.  Gives  off 
arsenical  (alliaceous)  fumes  before  the  blowpipe,  and  fuses  to 
a  pale  globule,  which  darkens  on  exposure.  Assumes  a 
green  coating  in  nitric  acid,  and  is  dissolved  in  aqua-regia. 

Diff.  Distinguished  from  pyrite  and  linnaeite  by  its  pale 
reddish  shade  of  color,  and  also  its  arsenical  fumes,  and 
from  much  of  the  latter  by  not  giving  a  blue  color  with 
borax.  None  of  the  ores  of  silver  with  a  metallic  lustre 
have  a  pale  color,  excepting  native  silver  itself. 

Obs.  Accompanies  cobalt,  silver,  and  copper  ores  in  the 
mines  of  Saxony,  and  other  parts  of  Europe  ;  also  sparingly 
in  Cornwall. 

It  is  found  at  Chatham,  Conn.,  in  gneiss,  associated  with 
white  nickel  or  cloanthite. 

Skutterudite.  A  cobalt  arsenide  of  the  formula  Co  As3,  from  Skut- 
terud,  Norway. 

Breithauptite  or  Antimonicd  Nickel.  Ni  Sb= Antimony  67 '8,  nickel 
32-2  =  100.  It  has  a  pale  copper-red  color,  inclining  to  violet.  H.— 5'5 
-6.  G.=7'54  Crystals  hexagonal.  From  Andreasberg. 

Gersdorffite.  A  nickel  arsenosulphide  ;  NiS2  +  Ni  As2=:Ni  AsS= 
Arsenic  45 '5,  sulphur  19 '4,  nickel  35 •!,  but  varying  much  in  composi- 
tion. Color  sulphur- white  to  steel-gray.  H.  =5'5.  G.=5'6-6-9. 

Ullmatmite  or  Nickel  Stibine.  An  antimonial  nickel  sulphide,  con- 
taining 25  to  28  per  cent,  of  nickel.  Color  steel-gray,  inclining  to  sil- 
ver-white. In  cubical  crystals,  and  also  massive.  H.=:5-5'5.  G.  =6'45. 
From  the  Duchy  of  Nassau. 

Grunauite  or  Bismuth  Nickel.  A  sulphide  containing  31  to  38*5  of 
sulphur,  10  to  14  per  cent,  of  bismuth,  with  22  to  40 '7  of  nickel. 
Color  light  steel --gray  to  silver- white  ;  often  tarnished  yellowish.  H.  = 
4-5.  G.  =5-13.  From  the  district  of  Altenkirchen,  Prussia. 


COBALT   AND   NICKEL.  167 

Asbolite.— Earthy  Cobalt.     Black  Cobalt  Oxide. 

Earthy,  massive.  Color  black  or  blue-black.  Soluble  in 
muriatic  acid,  with  an  evolution  of  fumes  of  chlorine. 

Obs.  Occurs  in  an  earthy  state  mixed  with  oxide  of  man- 
ganese as  a  bog  ore,  or  secondary  product.  Abundant  at 
Mine  La  Motte,  Missouri,  and  also  near  Silver  Bluff,  South 
Carolina.  The  analyses  vary  in  the  proportion  of  oxide  of 
cobalt  associated  with  the  manganese,  as  the  compound  is  a 
mere  mixture.  Sulphide  of  cobalt  occurs  with  the  oxide. 
The  Carolina  ores  afforded  Cobalt  oxide  24,  manganese 
oxide  76.  The  ore  from  Missouri,  as  analyzed  by  Prof. 
Silliman,  afforded  40  per  cent,  of  cobalt  oxide,  with  oxides 
of  nickel,  manganese,  iron  and  copper. 

This  ore  has  been  found  abroad  in  France,  Germany, 
Austria,  and  England. 

The  ore  is  purified  and  made  into  smalt,  for  the  arts. 

Erythrite. — Cobalt  Bloom.     Hydrous  Cobalt  Arsenate. 

Monoclinic.  In  oblique  crystals  having  a  highly  perfect 
cleavage,  like  mica  ;  laminae  flexible  in  one  direction.  Also 
as  an  incrustation,  and  in  reniform  shapes,  sometimes  stel- 
late. 

Color,  peach-red,  crimson-red,  rarely  grayish  or  greenish  ; 
streak  a  little  paler,  the  dry  powder  lavender-blue.  Lustre 
of  laminae  pearly  ;  earthy  varieties  without  lustre.  Trans- 
parent to  subtranslu  cent.  H.  —  1  '5-2.  G.  =  2. 95. 

Composition.  Co308As2  +  8aq  =  Arsenic  acid  38-4,  oxide 
of  cobalt  37 -6,  water  24-6.  B.B.  on  charcoal  gives  arsen- 
ical fumes  and  fuses  ;  yields  a  blue  glass  with  borax. 

The  earthy  ore  is  sometimes  called  peach-blossom  ore,  from 
its  color;  and  also  red  cobalt,  ochre.  Kottigite  is  a  kind 
containing  zinc. 

Diff.  Eesembles  red  antimony,  but  that  species  wholly 
volatilizes  before  the  blowpipe.  From  red  copper  ore  it 
differs  in  giving  a  blue  glass  with  borax ;  moreover,  the 
color  of  the  copper  ore  is  more  sombre. 

Obs.  Occurs  with  ores  of  lead  and  silver,  and  other  co- 
balt ores.  Schneeberg,  in  Saxony;  Saalfield,  in  Thuringia  ; 
and  Riechelsdorf,  in  Hessia,  are  noted  European  localities. 
It  is  found  also  in  Dauphiny,  Cornwall,  and  Cumberland. 

Valuable  as  an  ore  of  cobalt  when  abundant. 


168  DESCRIPTIONS   OF  MINERALS. 

Roselite  is  a  rose-red  triclinic  arsenate  of  cobalt. 

Bieberite  or  Cobalt  Vitriol.  Has  a  flesh-red  or  rose-red  tint,  and 
astringent  taste.  Co  04  S + 7aq  =  Sulphuric  acid  28 '4,  cobalt  oxide 
25'5,  water  461. 

Morenosite.  A  nickel  vitriol,  Ni  O4  S  +  7aq,  having  apple-green  to 
greenish- white  color.  Lindackerite,  hydrous  nickel -copper  arsenate. 

Zaratite  or  Emerald  Nickel.  Incrusting,  minute  globular  or  stalac- 
titic.  Color  bright  emerald-green.  Lustre  vitreous.  Transparent  or 
nearly  so.  H.  =;3-3'25.  G.  — 2'5-2'7.  It  is  a  nickel  carbonate,  con- 
taining nearly  30  per  cent,  of  water.  B.B.  infusible  alone,  but  loses 
its  color.  Occurs  with  chromic  iron  and  magnesium  carbonate  on 
serpentine,  in  Lancaster  County,  Pennsylvania. 

Remingtonite.  A  hydrous  cobalt  carbonate,  rose-colored,  from 
Finksburg,  Md. 

Spherocobaltite.     A  cobalt  carbonate,  Co  O3  C,  from  Saxony. 

Nickel  Silicates.  Genthite  is  a  hydrous  magnesium  and  nickel  sili- 
cate, of  a  pale  apple-green  color,  yielding  in  one  analysis  30  per  cent, 
of  nickel  oxide.  From  Texas,  Lancaster  County,  Pa.,  and  other 
localities.  Rottisite,  from  Rottis,  Voigtland,  is  similar.  Pimelite  is 
an  impure  apple-green  silicate,  affording  in  one  case  15 '6  per  cent,  of 
nickel  oxide.  Alipite  is  similar ;  so  also  Oarnierite  (and  Noumeite), 
from  New  Caledonia,  and  worked  there  for  nickel. 

General  Remarks. — The  two  arsenical  ores  of  cobalt  afford  the 
greater  part  of  the  cobalt  of  commerce.  The  earthy  oxide  when 
abundant  is  a  profitable  source  of  the  metal.  Erythrite  (Cobalt 
Bloom)  occurs  abundantly  with  other  cobalt  ores  at  its  localities  in 
Saxony,  Thuringia  and  Hesse  Cassel.  Arsenopyrite  (mispickel)  yields 
at  times  5  to  9  per  cent,  of  cobalt.  Cobalt  is  never  employed  in 
the  arts  in  a  metallic  state,  as  its  alloys  are  brittle  and  unimpor- 
tant. It  is  chiefly  used  for  painting  porcelain  and  pottery,  and  is 
required  for  this  purpose  in  the  state  of  an  oxide,  or  the  silicated 
oxide  called  smalt  and  azure.  Zaffre  is  an  impure  oxide  obtained  in 
the  calcining  of  the  ore  with  twice  its  weight  of  sand;  and  from  it 
the  smalt  and  azure  are  produced.  Nickel  is  worked  in  Germany, 
Austria,  Russia,  Sweden,  England,  United  States,  and  New  Caledonia. 
It  is  obtained  largely  from  the  copper  nickel  (niccolite)  and  chloan- 
thite,  or  from  an  artificial  product  called  speiss  (an  impure  arsenide), 
derived  from  roasting  ores  of  cobalt  containing  nickel ;  from  siegenite 
(or  nickel-linnaeite),  a  sulphide  of  cobalt  and  nickel  ;  from  millerite), 
in  part  ;  from  the  apple-green  silicate  ;  and  largely  from  pyrrhotite 
or  "magnetic  iron  pyrites."  At  the  Gap  Mine,  near  Lancaster,  Pa., 
the  ore  is  millerite  and  pyrrhotite  ;  in  Missouri,  the  siegenite ;  in 
New  Caledonia,  chiefly  the  silicate. 

Nickel  also  occurs  in  meteoric  iron,  forming  an  alloy  with  the  iron, 
which  is  characteristic  of  most  meteorites.  The  proportion  sometimes 
exceeds  20  per  cent. 

As  nickel  does  not  rust  or  oxidize  (except  when  heated),  it  is  supe- 
rior to  steel  for  the  manufacture  of  many  philosophical  instruments. 
An  alloy  of  copper,  nickel,  and  zinc  (one-sixth  to  one-third  nickel), 
constitutes  the  German  silver,  or  argentane. 

"  German  silver "  is  not  a  very  recent  discovery.  In  the  reign  of 
William  III.,  an  act  was  passed  making  it  felony  to  Uanch  copper  in 


URANIUM.  1(59 

imitation  of  silver,  or  mix  it  with  silver  for  sale.  "  Wliite  copper" 
has  long  been  used  in  Saxony  for  various  small  articles ;  the  alloy 
employed  is  stated  to  consist  of  copper  88 '00,  nickel  8 '75,  sulphur 
with  a  little  antimony  0'75,  silex,  clay,  and  iron  1*75.  A  similar 
alloy  is  well  known  in  China,  and  is  smuggled  into  various  parts  of 
the  East  Indies,  where  it  is  called  packfong.  It  has  been  sometimes 
identified  with  the  Chinese  tutenague.  M.  Meurer  analyzed  the  white 
copper  of  China,  and  found  it  to  consist  of  copper  65*24,  zinc  19 '52, 
nickel  13,  silver  2 '5,  with  a  trace  of  cobalt  and  iron.  Dr.  Fyfe  ob- 
tained copper  40*4,  nickel  31 '6,  zinc  25'4,  and  iron  2 '6.  It  has  the 
color  of  silver,  and  is  remarkably  sonorous.  It  is  worth  in  China 
about  one-fourth  its  weight  of  silver,  and  is  not  allowed  to  be  carried 
out  of  the  empire. 

An  alloy  of  88  per  cent,  copper  and  12  per  cent,  nickel  is  the  mate- 
rial of  the  United  States  cent,  introduced  in  1851.  Switzerland,  Bel- 
gium and  Jamaica  also  have  used  a  nickel  alloy  for  coins. 

Nickel  is  mostly  used  at  the  present  time  for  nickel-plating  by 
electro  deposition.  The  value  of  the  metal  in  commerce  rose  in  the 
years  1870  to  1875,  from  $1.25  to  $3.00  per  pound.  The  amount 
annually  produced  is  about  600  tons. 

URANIUM. 

Uranium  ores  have  a  specific  gravity  not  above  7,  and  a 
hardness  below  6.  The  ores  are  either  of  some  shade  of  light 
green  or  yellow,  or  they  are  dark  brown  or  black  and  dull,  or 
submetallic  and  without  a  metallic  lustre  when  powdered. 
They  are  not  reduced  when  heated  with  carbonate  of  soda ; 
and  the  brown  or  black  species  fuse  with  difficulty  on  the 
edges  or  not  at  all. 

Uraninite. — Pitchblende.     Uranium  Oxide. 

Isometric.  In  octahedrons  and  related  forms.  Also  mas- 
sive and  botryoidal.  Color  grayish,  brownish,  or  velvet- 
black.  Lustre  submetallic  or  dull.  Streak  black.  Opaque. 
•H.=5-5.  G.=6-47. 

Composition.  75  to  87  per  cent,  of  uranium  oxides  with 
silica,  lead,  iron,  and  some  other  impurities.  Related  to 
the  spinel  group.  B.B.  infusible  alone  ;  a  gray  scoria  with 
borax.  Dissolves  slowly  in  nitric  acid,  when  powdered. 

Obs.  Occurs  in  veins  with  ores  of  lead  and  silver  in 
Saxony,  Bohemia,  and  Hungary ;  also  in  the  tin  mines  of 
Cornwall,  near  Eedruth.  In  the  United  States,  very  spar- 
ingly at  Middletown,  Redding,  and  Haddam,  Conn. ;  in  Nortb 
Carolina ;  on  the  north  side  of  Lake  Superior  (Coracite). 


170  DESCRIPTIONS   OF   MINERALS. 

The  oxides  of  uranium  are  used  in  painting  upon  porce- 
lain, yielding  a  fine  orange  in  the  enameling  tire,  and  a 
black  color  in  that  in  which  the  porcelain  is  baked. 

Cleveit?.  Hydrated  oxide  of  uranium,  iron,  erbium,  cerium,  yttrium, 
in  cubic  forms.  From  Norway. 

Oummite,  An  amorphous  uranium  ore,  looking  like  gum,  of  a  red- 
dish or  brownish  color.  It  is  a  hydrous  uraninite,  and  has  resulted 
from  its  alteration.  Occurs  at  Johanngeorgenstadt,  and  in  North  Caro- 
lina. 

Eliasite.  Another  hydrous  ore,  more  or  less  resin-like  in  aspect,  of 
a  reddish-brown  to  black  color. 

Hatchettolite.  A  hydro  as  columbo-tantalate  of  uranium,  in  isome- 
tric octahedrons,  resembling  pyrochlore  from  North  Carolina.  G.  = 
4-76-4-84. 

Blomstrandite.     A  hydrous  titano-columbate,  from  Sweden. 

Torbernite. — Uranite.     Chalcolite.     Uran-Mica. 

Dimetric.  In  square  tables,  thinly  foliated  parallel  to  the 
base,  almost  like  mica  ;  laminae  brittle. 

Color  emerald  and  grass-green ;  streak  a  little  paler. 
Lustre  of  laminae  pearly.  Transparent  to  subtranslucent. 
H.  =  2-2-5.  G.- 3 -4-3 -6. 

Composition.  A  uranium-copper  phosphate,  consisting  if 
pure  of  Phosphorus  pentoxide  15-1,  uranium  trioxide  61-3, 
copper  oxide  8  '4,  water  15-3  =  100.  B.B.  fuses  to  a  blackish 
mass,  and  colors  the  flame  green. 

Diff.  The  micaceous  structure,  connected  with  the  bright 
green  color  and  square  tabular  form  of  the  crystals,  are  strik- 
ing characters.  The  folia  of  mica  are  not  brittle,  like  those 
of  uranite. 

Obs.  Occurs  with  uranium,  silver  and  tin  ores.  It  is 
found  at  St.  Symphorien,  in  splendid  crystallizations,  near 
Redruth  and  elsewhere  in  Cornwall ;  in  the  Saxon  and 
Bohemian  mines  ;  in  North  Carolina. 

Autunite  is  similar  to  torbernite  ;  but  has  a  bright  citron-yellow 
color,  and  is  a  uranium-calcium  phosphate.  From  the  same  mining 
^regions,  also  from  near  Autun  in  France,  and  sparingly,  from  Portland, 
Middletown,  and  Redding,  Conn.;  Acworth,  N.  H. ;  Chesterfield,  Mass.; 
and  in  North  Carolina. 

Uranospinite  is  an  autunite  containing  arsenic  instead  of  phos- 
phorus ;  and  Zeunerite  is  a  torbernite  containing  arsenic  instead  of 
phosphorus. 

Samarskite  (formerly  named  uranotantalite  and  yttroilmenite)  is  a 
compound  of  oxyd  of  uranium  with  columbic  and  tungstic  acids,  from 
Miask  in  the  Ural.  It  is  of  a  dark  brown  color  and  submetallic  lustre. 
H=5'5.  G.=5'4-5'7.  Abundant  in  North  Carolina. 


IRON.  171 

Johannite  or  Uranmtriol  is  a  sulphate  of  uranium.  It  has  a  fine 
emerald-green  color,  and  a  bitter  taste.  From  Bohemia. 

Trdgerite  and  Walpurg&e  are  uranium  arsf  nates.  Voglite  and 
Liebigite  are  uranium  carbonates.  Johnnnite  is  a  uranium  vitriol  ; 
Uranochalcitc ,  Medijdile,  Zippeite,  Voglianite,  Uraconite,  are  other 
uranium  sulphates. 

Uranocircite  is  a  hydrous  barium-uranium  phosphate. 

IRON. 

Iron  occurs  native,  and  alloyed  with  nickel  in  meteoric  iron. 
Its  most  abundant  ores  are  the  oxides  and  sulphides.  It  is 
also  found  combined  with  arsenic,  forming  arsenides  and 
sulpharsenides  ;  with  oxygen  and  other  metals,  as  chro- 
mium, aluminum,  magnesium  ;  and  in  the  condition  of  sul- 
phate, phosphate,  arsenate,  columbate,  silicate  and  carbon- 
ate, of  which  the  last  is  an  abundant  and  valuable  ore. 
Its  ores  are  widely  disseminated.  The  oxides  and  silicates 
are  the  ordinary  coloring  ingredients  of  soils,  clays,  earth  and 
many  rocks,  tinging  them  red,  yellow,  dull  green,  brown, 
and  black. 

The  ores  have  a  specific  gravity  below  8,  and  the  ordinary 
workable  ores  seldom  exceed  5.  Many  of  them  are  infusible 
before  the  blowpipe,  and  nearly  all  minerals  containing  iron 
become  attractable  by  the  magnet  after  heating,  when  not 
so  before.  By  their  difficult  fusibility,  the  species  with  a 
metallic  lustre  are  distinguished  from  ores  of  silver  and  cop- 
per, and  also  more  decidedly  from  these  and  other  ores  by 
blowpipe  reaction. 

Native  Iron. 

Isometric.     Usually  massive  with  octahedral  cleavage. 

Color  and  streak  iron-gray.  Fracture  hackly.  Malleable 
and  ductile.  H.  =4 -5.  G.  =7 -3-7 -8.  Acts  strongly  on  the 
magnet. 

Obs.  Native  iron  occurs  in  grains  disseminated  through 
some  doleryte,  basalt,  and  other  related  igneous  rocks  ;  and 
in  Greenland,  in  very  large  masses  in  such  igneous  rocks, 
the  largest  weighing  over  a  ton.  It  is  suggested  by  J. 
Lawrence  Smith,  that  the  iron  was  reduced  "by  means  of 
carbohydrogen  vapors,  taken  into  the  rock  from  carbonaceous 
rocks  passed  through  on  the  way  to  the  surface. 


172 


DESCRIPTIONS   OP   MINERALS. 


It  is  a  constituent  of  nearly  all  meteorites,  and  the  chief 
ingredient  in  a  large  part  of  them  ;  and  in  this  state  it  is 
with  a  rare  exception  alloyed  with  nickel,  and  with  traces 
of  cobalt  and  copper.  The  Texas  meteorite,  of  Yale  College, 
weighs  1,635  pounds  ;  the  Pallas  meteorite,  now  at  Vienna, 
originally  1,600  ;  but  one  in  Mexico,  the  San  Gregorio 
meteorite,  is  stated  to  weigh  five  tons ;  and  one  in  the  dis- 
trict of  Chaco-Gualamba,  S.  A.,  nearly  fifteen  tons.  Meteoric 
iron  often  has  a  very  broad  crystalline  structure,  long  lines 
and  triangular  figures  being  developed  by  putting  nitric  acid 
on  a  polished  surface.  The  coarseness  of  this  structure  dif- 
fers in  different  meteorites,  and  serves  to  distinguish  speci- 
mens not  identical  in  origin.  Nodules  of  troilite  (FeS), 
and  schreibersite  (iron  phosphide)  are  common  in  iron  me- 
teorites. Meteoric  iron  may  be  worked  like  ordinary  malle- 
able iron.  The  nickel  diminishes  the  tendency  to  rust.  But 
some  kinds  contain  iron  chloride,  or  are  open  in  texture,  and 
rust  badly. 

Pyrite. — Iron  Pyrites.     Iron  Bisulphide. 


Isometric.     Usually  in  cubes,  the  strise  of  one  face  at  right 
angles  with  those  of  either  adjoining  face,  as  in  fig.  1.     Also 


IRON.  173 

figs.  2  to  7  ;  also  figs.  8  to  15  on  page  6.  Fig.  6,  a  pentag- 
onal dodecahedron,  is  a  common  form.  Occurs  also  in  imi- 
tative shapes,  and  massive. 

Color  brass-yellow  ;  streak  brownish  black.  Lustre  of 
crystals  often  splendent  metallic.  Brittle.  H.  =  6-6-5,  be- 
ing hard  enough  to  strike  fire  with  steel.  G.  =4:  -8-5-1. 

Composition.  Fe  S2  —  Sulphur  53-3,  iron  46-7  =  100. 
B.B.  on  charcoal  gives  off  sulphur,  and  ultimately  affords 
a  globule  attractable  by  the  magnet. 

Pyrite  often  contains  a  minute  quantity  of  gold,  and 
is  then  called  auriferous  pyrite.  See  under  Gold.  Nickel, 
cobalt  and  copper  occur  in  some  pyrite. 

Diff.  Distinguished  from  copper  pyrites  in  being  too  hard 
to  be  cut  by  a  knife,  and  also  in  its  paler  color.  The  ores 
of  silver,  at  all  resembling  pyrite,  instead  of  having  its  pale 
bronze-yellow  color,  are  steel-gray  or  nearly  black  ;  and  be- 
sides, they  are  easily  scratched  with  a  knife  and  quite  fusible. 
Gold  is  sectile  and  malleable. 

Obs.  Pyrite  is  one  of  the  most  common  ores  on  the 
globe.  It  occurs  in  rocks  of  all  ages.  Cornwall,  Elba, 
Piedmont,  Sweden,  Brazil,  and  Peru,  have  afforded  magnifi- 
cent crystals.  Alston  Moor,  Derbyshire,  Kongsberg  in  Nor- 
way, are  well-known  localities.  It  has  also  been  observed  in 
the  Vesuvian  lavas,  and  in  many  other  igneous  rocks. 

In  the  United  States,  the  localities  are  numerous.  Fine 
crystals  have  been  met  with  at  Eossie,  N.  Y.  ;  at  many 
other  places  in  that  State  ;  also  in  each  of  the  New  England 
States  and  in  Canada  ;  in  New  Jersey,  Pennsylvania,  Vir- 
ginia, North  Carolina,  Georgia,  in  Colorado,  Wyoming  and 
the  States  west.  It  occurs  in  all  gold  regions,  and  is  one 
source  of  gold. 

This  species  is  of  the  highest  importance  in  the  arts, 
although  not  affording  good  iron  on  account  of  the  diffi- 
culty of  separating  entirely  the  sulphur.  It  affords  the 
greater  part  of  the  sulphate  pf  iron  (green  vitriol  or  copperas) 
and  sulphuric  acid  (oil  of  vitriol)  of  commerce,  and  also 
a  considerable  portion  of  the  sulphur  and  alum.  To  make 
the  sulphate  the  pyrites  is  sometimes  heated  in  clay  retorts, 
by  which  about  17 "per  cent,  of  sulphur  is  distilled  over  and 
collected.  The  ore  is  then  thrown  out  into  heaps,  exposed 
to  the  atmosphere,  when  a  change  ensues  by  which  the  re- 
maining sulphur  and  iron  become  through  oxidation  sul- 
phate of  iron.  The  material  is  lixiviated,  and  partially  eva- 


174  DESCRIPTIONS   OF  MINERALS. 

porated,  preparatory  to  its  being  run  off  into  vats  or  troughs 
to  crystallize.  In  other  instances,  the  ore  is  coarsely  broken 
up  and  piled  in  heaps  and  moistened.  Fuel  is  sometimes 
used  to  commence  the  process,  which  afterwards  the  heat 
generated  continues.  Decomposition  takes  place  as  before, 
with  the  same  result.  Cabinet  specimens  of  pyrite,  espe- 
cially granular  or  amorphous  masses,  often  undergo  a  spon- 
taneous change  to  the  sulphate,  particularly  when  the  atmo- 
sphere is  moist. 

Pyrite,  owing  to  its  tendency  to  oxidation,  and  its  very 
general  distribution  in  rocks  of  all  kinds  and  ages,  is  one  of 
the  chief  sources  of  the  disintegration  and  destruction  of 
rocks.  No  granite,  sandstone,  slate,  or  limestone,  contain- 
ing it,  is  fit  for  architectural  purposes  or  for  any  outdoor 
uses.  The  same  destructive  effects  come  from  pyrrhotite  and 
marcasite,  which  also  are  widely  diffused. 

The  name  pyrites  is  from  the  Greek  pur,  fire,  because,  as 
Pliny  states,  "there  was  much  fire  in  it,"  alluding  to  its 
striking  fire  with  steel.  Thi.3  ore  is  the  mundic  of  miners. 

Marcasite  or  White  iron  pyrites.  This  ore  has  the  same  composition  as 
pyrites,  but  differs  in  crystallizing  in  trimetic  forms.  /A/=106°  36 . 
The  color  is  a  little  paler  than  that  of  pyrite,  and  it  is  more  liable  to 
decomposition  ;  hardness  the  same  ;  specific  gravity  4'6-4'85.  Radi- 
ated pyrites,  Hepatic  pyrites,  Cockscomb  pyrites  (alluding  to  its  crested 
shapes;,  and  Spear  pyrites,  are  names  of  some  of  its  varieties.  It  oc- 
curs in  crystals  at  Warwick  and  Phillipstown,  N.  Y.  Massive  varie- 
ties are  met  with  at  Cummington,  Mass.;  Monroe,  Trumbull,  and 
East  Haddam,  Conn. ;  and  at  Haverhill,  N.  H. 

Pyrrhotite. — Magnetic  Pyrites.     Iron  Sulphide. 

Hexagonal.  Occurs  occasionally  in  hexagonal  prisms, 
which  are  often  tabular ;  generally  missive. 

Color  between  bronze-yellow  and  copper-red  ;  streak  dark 
grayish-black.  Brittle.  H.  =3-5 -4-5.  G.=4«4-4;65. 
Slightly  attracted  by  the  magnet.  Liable  to  speedy  tarnish. 

Composition.  Fe7  S8=:  Sulphur  39-5,  iron  60-5.  It  is 
often  a  valuable  ore  of  nickel,  containing  sometimes  3  to 
5  per  cent,  of  this  metal.  B.B.  on  charcoal  in  the  outer 
flame  it  is  converted  into  red  oxide  of  iron.  In  the  inner 
flame  it  fuses  and  glows,  and  affords  a  black  globule  which 
is  magnetic,  and  has  a  yellowish  color  on  a  surface  of  frac- 
ture. 

Diff.  Its  inferior  hardness  and  shade  of  color,  and  its 


IRON.  175 

magnetic  quality  distinguish  it  from  pyrite ;  and  its  pale- 
ness of  color  from  chalcopyrite  or  copper  pyrites. 

Obs.  Crystallized  specimens  have  been  found  at  Kongs- 
berg  in  Norway,  and  at  Andreasberg  in  the  Hartz.  The 
massive  variety  is  found  in  Cornwall,  Saxony,  Siberia,  and 
the  Hartz  ;  also  at  Vesuvius  and  in  meteoric  stones. 

In  the  United  States,  it  is  met  with  at  Trumbull  and 
Monroe,  New  Fairfield,  and  Litchfield,  Conn.  ;  at  Straff ord 
and  Shrewsbury,  Vt. ;  at  Corinth,  New  Hampshire;  in 
many  parts  of  Massachusetts  and  New  York ;  at  Lancaster, 
Pa.,  where  it  is  worked  for  nickel.  It  is  used  for  making 
green  vitriol  and  sulphuric  acid,  like  pyrite. 

Troilite  is  a  similar  mineral  of  the  formula  Fe  S,  occur- 
ring in  meteorites.  Schreibersite  is  a  phosphide  of  iron  and 
nickel,  occurring  in  meteorites. 

Arsenopyrite. — Mispickel.     Arsenical  Iron  Pyrites. 

Trimetric.  In  rhombic  prisms,  with  cleavage  parallel  to 
the  faces  /;  /A/=lll°  40'  to  112°. 
Crystals  sometimes  elongated  horizon- 
tally, producing  a  rhombic  prism  of 
100°  nearly,  with  /  and  /  the  end 
planes.  Occurs  also  massive. 

Color  silver-white ;  streak  dark 
grayish-black.  Lustre  shining.  Brit- 
tle. H.=5-5-G.  G.=6-3. 

Composition.  Fe  AsS  —  Arsenic  46  -0, 
sulphur  19-6,  iron  34-4=100.  A  co- 

baltic  variety  contains  4  to  9  per  cent,  of  cobalt  in  place 
of  part  of  the  iron ;  Danaite  of  New  Hampshire,  consists 
of  Arsenic  41-4,  sulphur  17-8,  iron  32-9,  cobalt  6-5.  B.B. 
affords  arsenical  fumes,  and  a  globule  of  iron  sulphide 
which  is  attracted  by  the  magnet.  In  the  closed  tube  a 
sublimate  of  arsenic  sulphide.  Gives  fire  with  a  steel  and 
emits  a  garlic  odor. 

Diff.  Eesembles  arsenical  cobalt,  but  is  much  harder, 
it  giving  fire  with  steel;  it  differs  also  in  yielding  a  mag- 
netic globule  before  the  blowpipe,  and  in  not  affording  the 
reaction  of  cobalt  with  the  fluxes. 

Obs.  Arsenopyrite  is  found  mostly  in  crystalline  rocks,  and 
is  commonly  associated  with  ores  of  silver,  lead,  iron,  or  cop- 
per. It  is  abundant  at  Freiberg,  Munzig,  and  elsewhere  in 
Europe,  and  also  in  Cornwall,  England. 


176  DESCRIPTIONS    OF   MINERALS. 

It  occurs  in  crystals  in  New  Hampshire,  at  Franconia, 
Jackson,  and  Haverhill ;  in  Maine,  at  Blue  Hill  Bay,  Corinth, 
Newfield,  and  Thomaston  ;  in  Vermont,  at  Waterbury ;  in 
Massachusetts,  massive  at  Worcester  and  Sterling ;  in  Con- 
necticut, at  Chatham,  Derby,  and  Monroe  ;  in  New  Jersey, 
at  Franklin ;  in  New  York,  in  Lewis,  Essex  County,  and 
near  Edenville  and  elsewhere  in  Orange  County  ;  in  Kent, 
Putnam  County. 

Leucopyrite.  This  is  the  name  of  arsenical  iron  Fe2  As3.  It  re- 
sembles the  preceding  in  color  and  in  its  crystals.  I  f\  7=122°  20'. 
It  has  less  hardness  and  higher  specific  gravity.  H.  =5-5*5.  G.  =7'2 
-7 '4.  Contains  Iron  32  '2,  arsenic  GO  '9,  with  some  sulphur.  From 
Styria,  Silesia,  and  Carinthia. 

Lollingite  is  another  iron  arsenide,  Fe  As.2=Arsenic  72'8,  iron  27'2  ; 
specific  gravity  6 '8-8 '71.  Berthierite  is  an  iron  sulphantimonite. 

Hematite. — Specular  Iron  Ore.     Iron  Sesquioxide. 

Khombohedral.     In  complex  modifications  of  a  rhombohe- 

3. 


dron  of  86°  10'  (fig.  1);  crystals  occasionally  thin  tabular. 
Cleavage  usually  indistinct.  Often  massive  granular  ;  some- 
times lamellar  or  micaceous.  Also  pulverulent  and  earthy. 
Color  dark  steel-gray  or  iron-black,  and  often  when  crys- 
tallized having  a  highly  splendent  lustre ;  streak-powder 
cherry-red  or  reddish -brown.  The  metallic  varieties  pass 
into  an  earthy  ore  of  a  red  color,  having  none  of  the  external 
characters  of  the  crystals,  but  perfectly  corresponding  to  them 
when  they  are  pulverized,  the  powder  they  yield  being  of  a 
deep  red  color,  and  earthy  or  without  lustre.  Gr.  =4-5-5 -3. 
Hardness  of  crystals  5 -5-6 -5.  Sometimes  slightly  attracted 
by  the  magnet. 

VARIETIES. 

Specular  iron.     Having  a  perfectly  metallic  lustre. 
Micaceous  iron.     Structure  foliated. 
Red  hematite.    Submetallic,  or  unmetallic,  and  of  a  brown- 
ish-red color. 

Red  ochre.     Soft  and  earthy,  and  often  containing  clay. 


IRON.  177 

Red  chalk.  More  firm  and  compact  than  red  ochre,  and 
of  a  fine  texture. 

Jasper  y  clay  iron.  A  ha1*d  impure  siliceous  clayey  ore, 
and  having  a  brownish-red  jaspery  look  and  compactness. 

Clay  iron  stone.  The  same  as  the  last,  the  oolor  and  ap- 
pearance less  like  jasper.  But  this  is  one  variety  only  of 
what  is  called  "clay  iron  stone,"  a  name  covering  also  a  re- 
lated variety  of  siderite  and  limonite. 

Lenticular  argillaceous  ore.  A  red  ore,  consisting  of 
small  flattened  grains. 

Martite  is  hematite  in  octahedrons,  derived,  it  is  supposed, 
from  the  oxidation  of  magnetite. 

Composition.  Fe03  =  Oxygen  30,  iron  70  =  100.  B.B. 
alone  infusible.  Heated  in  the  inner  flame  it  becomes 
strongly  magnetic. 

Diff.  The  red  powder  of  this  mineral,  and  the  magnetism 
which  is  so  easily  induced  in  it  by  a  reduction  flame  dis- 
tinguish hematite  from  all  other  ores.  The  word  hematite, 
from  the  Greek  haima,  blood,  alludes  to  the  color  of  the 
powder. 

Obs.  This  ore  occurs  in  crystalline  and  stratified  rocks  of 
all  ages.  The  more  extensive  beds  of  pure  ore  abound  in 
Archaean  rocks ;  while  the  argillaceous  varieties  occur  in 
stratified  rocks,  being  often  abundant  in  coal  regions  and 
among  other  strata.  Crystallized  specimens  are  found  also 
in  some  lavas,  as  a  volcanic  product. 

Splendid  crystallizations  of  this  ore  come  from  Elba,  whose 
beds  were  known  to  the  Romans  ;  also  from  St.  Gothard  ; 
Arendal,  Norway ;  Longbanshyttan,  Sweden  ;  Lorraine  and 
Dauphiny.  Etna  and  Vesuvius  afford  handsome  specimens. 

In  the  "United  States,  this  is  an  abundant  ore.  The  two 
Iron  Mountains  of  Missouri,  situated  90  miles  south  of  St. 
Louis,  consist  mainly  of  this  ore,  piled  "  in  masses  of  all 
sizes  from  a  pigeon's  egg  to  a  middle-are  church."  One  of 
them  is  300  feet  high,  and  the  other,  the  "Pilot  Knob,"  is 
700  feet.  The  massive  and  micaceous  varieties  occur  there 
together  with  red  ochreous  ore.  Large  beds  occur  in  Essex, 
St.  Lawrence  and  Jefferson  counties,  N.  Y.,  and  at  Mar- 
quette,  in  Michigan;  the  micaceous  variety,  at  Hawley,  Mass., 
Piermont,  N.  H.,  and  in  Stafford  County,  Va.;  lenticular 
argillaceous  ore  abundantly  in  Oneida,  Herkimer,  Madison 
and  Wayne  counties,  N.  Y.,  constituting  one  or  two  beds  of 
the  Clinton  group  (tipper  Silurian),  in  a  compact  sandstone ; 


178  DESCRIPTIONS    OF    MINERALS. 

and  the  same  is  found  in  Pennsylvania  and  south  to  Alabama, 
and  also  in  Wisconsin  ;  it  contains  50  per  cent,  of  oxide  of 
iron,  with  about  25  of  carbonate  of  lime  and  more  or  less 
magnesia  and  clay.  The  coal  region  of  Pennsylvania  affords 
abundantly  the  clay  iron  ores,  but  they  are  mostly  either  the 
argillaceous  carbonate  or  limonite. 

Valuable  as  an  iron  ore,  though  less  easily  worked  when 
pure  and  metallic  than  the  magnetic  and  hydrous  ores.  Pul- 
verized red  hematite  is  used  for  polishing  metal.  Eed  chalk 
is  a  well-known  material  for  red  pencils. 

Menaccanite. — Ilmenite.     Titanic  Iron.     Washingtonite. 

Ehombohedral.  72A72-S50  31'.  Often  in  thin  plates  or 
seams  in  quartz  ;  also  in  grains.  Crystals  sometimes  very 
large  and  tabular. 

Color  iron-black  ;  streak  submetallic.  Lustre  metallic  or 
submetallic.  H.  =5-6.  G.  =4'5-5.  Acts  slightly  on  the 
magnetic  needle. 

Composition.  Like  that  of  hematite,  except  that  part  of 
the  iron  is  replaced  by  titanium  ;  the  amount  replaced  is 
very  variable.  Infusible  alone  before  the  blowpipe. 

Diff.  Near  specular  iron,  bat  its  powder  is  not  red. 

Obs.  Crystals,  an  inch  or  so  in  diameter,  occur  in  War- 
wick, Amity  and  Monroe,  Orange  County,  N.  Y.  ;  also  near 
Edenville  and  Greenwood  Furnace  ;  also  at  South  Royalston 
and  Goshen,  Mass.  ;  at  Washington,  South  Britain,  and 
Litchfield,  Conn.  ;  at  Westerly,  Rhode  Island. 
*  It  is  of  no  value  in  the  arts  and  is  a  deleterious  constitu- 
ent of  many  iron  ores. 

Magnetite. — Magnetic  Iron  Ore. 

Isometric.     Often  in  octahedrons  (fig.   1),  and  dodecahe- 
drons (fig.   2 ).  Cleavage  octahe-          g 
dral ;  sometimes  distinct.     Also 
granularly  massive.   Occasionally 
in  dendritic  forms  between  the 
folia  of  mica. 

Col  or  iron-black.  Streak  black. 
Brittle.     II.—  5*5-6-5.      G.=--5'0 
-5*1.     Strongly  attracted  by  the 
magnet,  and  sometimes  having  polarity. 

Composition.    Fe£e04=:FeO-f  Ee03= Oxygen  27'6,  iron 


IRON.  179 

72-4=100.  Infusible  before  the  blowpipe.  Yields  a  yellow 
glass  when  fused  with  borax  in  the  outer  flame. 

Diff.  The  black  streak  and  strong  magnetism  distinguish 
this  species  from  the  following. 

Obs.  Magnetic  iron  ore  occurs  in  extensive  beds,  and  also 
in  disseminated  crystals.  It  is  met  with  in  granite,  gneiss, 
mica  schist,  clay  slate,  syenyte,  hornblende  and  chlorite 
schist ;  and  also  sometimes  in  limestone. 

The  beds  at  Arendal,  and  nearly  all  the  Swedish  iron  ore, 
consist  of  massive  magnetic  iron.  At  Dannemora  and  the 
Taberg  in  Southern  Sweden,  and  also  in  Lapland  at  Kurun- 
avara  and  Gelivara,  there  are  mountains  composed  of  it. 

In  the  United  States  it  constitutes  extensive  beds,  in  Ar- 
chaean rocks,  in  Warren,  Essex,  Clinton,  Orange,  Putnam, 
Saratoga  and  Herkimer  counties,  New  York;  and  in  Sussex 
and  Warren  counties,  in  New  Jersey.  Smaller  deposits  occur 
in  the  several  New  England  States  and  Canada.  Also  found 
at  Magnet  Cove,  in  Arkansas ;  in  California,  in  Sierra 
County,  and  elsewhere.  It  exists  with  hematite  in  the  Iron 
Mountains  of  Missouri. 

Masses  of  this  ore,  in  a  state  of  magnetic  polarity,  consti- 
tute what  are  called  lodestones  or  native  magnets.  They  are 
met  with  in  many  beds  of  the  ore.  Siberia  and  the  Hartz 
have  afforded  fine  specimens ;  also  the  Island  of  Elba.  They 
also  occur  at  Marshall's  Island,  Maine;  also  near  Providence, 
Rhode  Island,  and  at  Magnet  Cove,  in  Arkansas.  The 
lodestone  is  called  magnes  by  Pliny,  from  the  name  of  the 
country,  Magnesia  (a  province  of  ancient  Lydia),  where  it 
was  found  ;  and  it  hence  gave  the  terms  magnet  and  mag- 
netism to  science. 


Franklinite. 

Isometric.  In  octahedral  and  dodecahedral  crystals.  Also 
coarse  granular  massive.  Color  iron-black ;  streak  dark 
reddish-brown.  Brittle.  H.^5'5-6'5.  G.  =4-85-51.  Usually 
is  attracted  by  the  magnet. 

Composition.  General  formula  like  that  of  magnetite, 
RE  04,  but  having  zinc  and  manganese  replacing  part  of  the 
iron,  as  indicated  in  the  formula  (Fe,  Zn,  Mn)  (fee,Mn)04. 
A  common  variety  corresponds  to  Fes  03  G7'6,  Fe  0  5 '8,  Zn  O 
6-9,  MnO  9-7=100. 

B.B.  with  soda  on  charcoal  a  zinc  coating  is  obtained  ;  a 


180  DESCRIPTIONS   OP  MINERALS. 

soda  bead  in  the  outer  flame  is  colored  green  by  the  manga- 
nese. 

Diff.  Resembles  magnetic  iron,  but  the  exterior  color  is  a 
more  decided  black.  The  streak  is  reddish  brown,  and  the 
blowpipe  reactions  are  distinctive. 

Obs.  This  is  an  abundant  ore  at  Sterling  and  Hamburg, 
in  New  Jersey,  near  the  Franklin  Furnace ;  at  the  former 
place  the  crystals  are  sometimes  four  inches  in  diameter ; 
also  amorphous  at  Altenberg,  near  Aix-la-Chapelle. 

Chromite. — Chromic  Iron. 

Isometric.  In  octahedral  crystals,  without  distinct  cleav- 
age. Usually  massive,  and  breaking  with  a  rough  unpolished 
surface. 

Color  iron-black  and  brownish  black  ;  streak  dark  brown. 
Lustre  submetallic  ;  often  faint.  H.  =5-5.  G.  =4*3-4-6. 
In  small  fragments  attractable  by  the  magnet. 

Composition.  General  formula  RR  04,  as  for  magnetite ; 
but  part  of  the  iron  is  replaced  by  chromium.  Analysis 
gives  Iron  protoxide  32,  chromium  sesquioxide  68  =  100; 
aluminum  and  magnesium  also  are  commonly  present  in 
variable  amounts,  replacing  the  other  constituents.  B.  B. 
infusible  alone  ;  with  borax  a  beautiful  green  bead. 

This  ore  usually  possesses  a  less  metallic  lustre  than  the 
other  black  iron  ores. 

Obs.  Occurs  usually  in  serpentine  rocks,  in  imbedded 
masses  or  veins.  Some  of  the  foreign  localities  are  the 
Gulsen  Mountains  in  Styria ;  the  Shetland  Islands  ;  the  de- 
partment of  Var  in  France  ;  Silesia,  Bohemia,  etc. 

In  the  United  States  it  is  abundant :  in  Maryland  in  the 
Bare  Hills,  near  Baltimore,  and  also  in  Montgomery  County, 
at  Cooptown,  in  Harford  County  ;  and  in  the  north  part  of 
Cecil  County  ;  occurs  also  in  Townsend  and  Westfield,  Ver- 
mont, and  at  Chester  and  Blandford,  Mass.  It  is  also  found 
in  Pennsylvania,  at  Wood's  Mine,  near  Texas,  Lancaster 
County,  in  West  Branford,  Chester  County ;  at  Bolton  and 
Ham,  Canada  East ;  in  California  near  New  Idria ;  also  in 
Sonoma  County  ;  Tuolumne  County,  near  Crimea  House, 
and  elsewhere  ;  at  Seattle  in  Wyoming. 

The  compounds  of  chromium,  which  are  extensively  used 
as  pigments,  are  obtained  chiefly  from  this  ore.  Meteorites 
have  afforded  a  chromium-sulphide,  named  Daubreelite. 


IRON.  181 

Limonite. — Brown  Hematite. 

Usually  massive,  and  often  with  a  smooth  botryoidal  or 
stalactitic  surface,  having  a  compact  fibrous  structure  with- 
in. Also  earthy. 

Color  dark  brown  and  black  to  ochre-yellow  ;  streak  yellow- 
ish brown  to  dull  yellow.  Lustre  sometimes  submetallic ; 
often  dull  and  earthy ;  on  a  surface  of  fracture  frequently 
silky.  H.=5-5-5.  G.=3'6-4. 

The  following  are  the  principal  varieties  : 

Brown  hematite.  The  botryoidal,  stalactitic  and  asso- 
ciated compact  ore. 

Brown  ochre,  Yelloiv  ochre.  Earthy  ochreous  varieties,  of 
a  brown  or  yellow  color. 

Brown  and  Yellow  day  iron  stone.  Impure  ore,  bard  and 
compact,  of  a  brown  or  yellow  color. 

Bog  iron  ore.  A  loose  earthy  ore  of  a  brownish-black 
color,  occurring  in  low  grounds. 

Composition.  Ee  09  H 6  ( = 2  Fe  03  +  3  H2  0)  —  Iron  sesqui- 
oxide  85-6,  water  14-4-100;  or  it  is  a  hydrous  iron  ses- 
quioxide,  containing,  when  pure,  about  two-thirds  its  weight 
of  pure  iron.  B.B.  blackens  and  becomes  magnetic;  with 
borax  in  the  outer  flame  a  yellow  glass. 

Diff.  This  is  a  much  softer  ore  than  either  of  the  two 
preceding,  and  is  peculiar  in  its  frequent  stalactitic  forms, 
and  in  its  affording  water  when  heated  in  a  glass  tube. 

Obs.  Occurs  connected  with  rocks  of  all  ages,  but  ap- 
pears, as  shown  by  the  stalactitic  and  other  forms,  to  have 
resulted  in  all  cases  from  the  decomposition  of  other  iron 
ores. 

An  abundant  ore  in  the  United  States.  Extensive  beds 
exist  in  Salisbury  and  Kent,  Conn. ,  also  in  the  neighboring 
towns  of  Beekman,  Fishkill,  Dover,  Amenia,  X.  Y.;  also  in 
a  similar  situation  north,  in  Richmond  and  West  Stock- 
bridge,  Mass.  ;  also  in  Bennington,  Monkton,  Pittsford, 
Putney,  and  Ripton,  Vermont.  *"  Large  beds  are  found  in 
Pennsylvania,  the  Carolinas,  near  the  Missouri  Iron  Moun- 
tains, and  also  in  Tennessee,  Iowa  and  Wisconsin. 

This  is  one  of  the  most  valuable  ores  of  iron.  The  limo- 
nite  of  Western  New  England,  and  that  along  the  same 
range  geologically  in  Dutchess  County,  New  York,  Eastern 
Pennsylvania,  and  beyond,  is  remarkably  free  from  phos- 
phorus, and  hence  is  highly  valued  for  its  iron.  Bog  orea 


182  DESCRIPTIONS   OF   MINERALS. 

usually  contain  much  phosphorus,  from  organic  sources, 
and  hence  the  iron  afforded  is  best  fitted  for  castings.  Li- 
monite  is  also  pulverized  and  used  for  polishing  metallic 
buttons  and  other  articles.  As  yellow  ochre,  it  is  a  common 
material  for  paint. 

Gothite  (Pyrrlwsidcrite,  Lepidokrokite)  is  another  iron  hydrate,  often 
in  prismatic  crystals,  as  well  as  fibrous  and  massive,  of  the  formula  Fe 
O4  H2( = Ee  O3  +  H,  O),  and  G.  =  4  -0-4 -4: 

Turgite  has  the  formula  EeO7  Ha=2EeO3  +  H20.  Xantho#iderit& 
and  limnite  are  other  related  hydrates. 

Melanterite. — Copperas.     Iron  Vitriol.     Green  Vitriol. 

Monoclinic.  In  acute  oblique  rhombic  prisms.  /  A  /= 
82°  21';  0  A  7=  80°  37'.  Cleavage  parallel  to  0  perfect. 
Generally  pulverulent  or  massive. 

Color  greenish  to  white.  Lustre  vitreous.  Subtranspa- 
rent  to  translucent.  Taste  astringent,  sweetish,  and  metal- 
lic. Brittle.  H.=2.  G.=l-83. 

Composition.  Fe  04S  4- 7aq=  Sulphur  trioxide  28-8,  iron 
protoxide  25-9,  water  45-3  =  100.  B.B.  becomes  magnetic. 
Yields  glass  with  borax.  On  exposure,  becomes  covered 
with  a  yellowish  powder,  which  results  from  oxidation. 

Obs.  This  species  is  the  result  of  the  decomposition  of 
pyrite  and  pyrrhotite,  which  readily  afford  it  if  moistened 
while  exposed  to  the  atmosphere,  and  it  is  obtained  from 
these  sulphides  for  the  arts  (p.  173).  An  old  mine  near 
Goslar,  in  the  Hartz,  is  a  noted  locality. 

Copperas  is  much  used  by  dyers  and  tanners,  on  account 
of  its  giving  a  black  color  with  tannic  acid,  an  ingredient  in 
nutgalls  and  many  kinds  of  bark.  It  for  the  same  reason 
forms  the  basis  of  ordinary  ink,  which  is  essentially  an  in- 
fusion of  nutgalls  and  copperas.  It  is  also  employed  in  the 
manufacture  of  Prussian  blue.  With  potassium  ferrocya- 
nide,  any  soluble  salt  of  iron  sesquioxicle,  even  in  minute 
quantity,  gives  a  fine  blue  color  to  the  solution  (due  to  the 
formation  of  Prussian  blue),  and  this  is  a  delicate  test  of  the 
presence  of  iron. 

CoquimUte,  Copiaptte,  Voltaitt,  Raimondite,  Botryogeri,  Fibroferrite, 
Ihleite,  are  names  of  other  hydrous  iron  sulphates  ;  and  Halotrichite 
is  an  iron-alum. 

Jarosite  is  a  hydrous  iron-potash  sulphate. 

Pisanite  is  an  iron-copper  vitriol. 

Lagonite.     A  hydrous  iron  borate,  from  the  Tuscan  lagoons. 


IRON. 


183 


Wolframite. — Wolfram.     Iron-Manganese  Tungstate. 

Monoclinic.  Sometimes  pseudomorphous  in  octahedrons 
formed  by  the  alteration  of  tungstate  of  lime.  Also  massive. 
Color  dark  grayish-blaok ;  streak  dark  reddish-brown. 
Lustre  submetallic,  shining,  or  dull.  H.  =5-5*5.  G.  = 
7-1-7-5. 

Composition.  (Fe,Mn)04W.  A  typical  variety  affords 
tungsten  trioxide  76*47,  iron  protoxide  9*49,  manganese 
protoxide  14*04=100.  A  manganese  wolframite  has  been 
named  Hiibnerite.  B.B.  fuses  easily  to  a  magnetic  globule  ; 
with  aqua  regia  dissolved  with  the  separation  of  yellow 
tungsten  trioxide. 

Found  often  with  tin  ores.  Occurs  in  Cornwall,  and  at 
Zinnwald  and  elsewhere  in  Europe.  In  the  United  States  it 
is  found  at  Monroe  and  Trumbull,  Conn. ;  on  Camdage 
Farm,  near  Blue  Hill  Bay,  Me. ;  near  Mine  la  Motte,  Mis- 
souri ;  in  the  gold  regions  of  North  Carolina  ;  in  Mammoth 
Mining  district,  Nevada  Hiibnerite. 

Columbite. 

Trimetric.     In  rectangular  prisms,  more  or  less  modified. 
Also  massive.     Cleavage  parallel    to 
the  lateral  faces  of  the  prism,  some- 
what distinct. 

Color  iron-black,  brownish-black ; 
often  with  a  characteristic  iridescence 
on  a  surface  of  fracture  ;  streak  dark 
brown,  slightly  reddish.  Lustre  sub- 
metallic,  shining.  Opaque.  Brittle. 
H.=r5-G.  G.=o-4-6-5. 

Composition.  Iron  columbate,  of 
the  formula  F  06  Cb.2  =  Columbium 
pentoxide  79'G,  iron  protoxide  16'4, 

manganese  protoxide  4'4,  tin  oxide  0'5,  lead  and  copper 
oxides  0*1  =  100.  Tantalum  often  replaces  part  of  the 
columbium,  and  in  this  case  the  mineral  is  of  higher  speci- 
fic gravity.  B.B.  alone  infusible.  It  imparts  to  the  borax 
bead  the  yellow  color  of  iron. 

Diff.  Its  dark  color,  submetallic  lustre,  and  a  slight  iri- 
descence, together  with  its  breaking  readily  into  angular 
fragments,  will  generally  distinguish  this  species  from  the 
ores  it  resembles. 


184  DESCRIPTIONS    OP    MINERALS. 

Ols.  Occurs  in  granite  at  Bodenmais  in  Bavaria,  and 
also  in  Bohemia.  In  the  United  States,  it  is  found  in  gra- 
nitic veins,  at  Middletown  and  Haddam,  Conn.  ;  at  Ches- 
terfield and  Beverly,  Mass.  ;  at  Ac  worth,  N.  H.  ;  Green- 
field, N.  Y.  A  crystal  was  found  at  Middletown,  which 
originally  weighed  14  pounds  avoirdupois  ;  and  a  part  of  it, 
6  inches  in  length  and  breadth,  weighing  6  Ibs.  12  oz.,  is  now 
in  the  collections  of  the  Wesleyan  University  of  that  place. 
Also  at  Standisb,  Maine  ;  and  in  granite  veins  in  North 
Carolina. 

This  mineral  was  first  made  known  from  American  speci- 
mens, by  Mr.  Hatchett,  an  English  chemist,  and  the  new 
metal  it  was  found  to  contain  was  named  by  him  columbium. 

Tantalite.  Fe(Mn)  O6  Ta2.  This  tantalate  of  iron  is  allied  to  colum- 
bite.  H.  6-6 '5.  G.  7-8.  It  is  distinguished  by  its  higher  specific 
gravity.  It  sometimes  contains  tin  and  tungsten.  From  Finland, 
Sweden,  near  Limoges  in  France,  and  from  North  Carolina  and 
Alabama. 

Note. — The  metal  named  Columbium  by  Hatchett,  is  the  same  that 
has  since  been  called  Niobium,  without  any  good  reason  for  the  change 
of  name. 

Triphylite.     An  iron  manganese-lithium  phosphate.     See  p.  190. 

Vivianite. — Hydrous  Iron  Phosphate. 

Monoclinic.  In  modified  oblique  prisms,  with  cleavage 
in  one  direction  highly  perfect.  Also  radiated,  reniform, 
and  globular,  or  as  coatings. 

Color  deep  blue  to  green.  Crystals  usually  green  at  right 
angles  with  the  vertical  axis,  and  blue  parallel  to  it.  Streak 
bluish.  Lustre  pearly  to  vitreous.  Transparent  to  translu- 
cent ;  opaque  on  exposure.  Thin  laminae  flexible.  H.  = 
1-5-2.  G.=2'66. 

Composition.  Pe3  08  P2  +  8aq  =  Phosphorus  pentoxide, 
28-3,  iron  protoxide  43-0,  water  28-7  =  100.  B.B.  fuses 
easily  to  a  magnetic  globule,  coloring  the  flame  greenish 
blue.  Affords  water  in  a  glass  tube,  and  dissolves  in  hydro- 
chloric acid. 

Diff.  The  deep  blue  color  and  the  little  hardness  are 
decisive  characteristics.  The  blowpipe  affords  confirma- 
tory tests. 

Obs.  Found  with  iron,  copper  and  tin  ores,  and  some- 
times in  clay,  or  with  bog  iron  ore.  St.  Agnes  in  Cornwall, 
Bodenmais,  and  the  gold  mines  of  Vorospatak  in  Transylva- 
nia, afford  fine  crystallizations.  In  the  United  States,  good 


IRON.  185 

crystals  have  been  found  at  Imlaystown,  N.  J.  At  Allentown, 
Monmonth  County,  and  Mullica  Hill,  Gloucester  County,  N. 
J.,  are  other  localities.  It  often  fills  the  interior  of  certain 
fossils.  Occurs  also  at  Harlem,  N.  Y.,  in  Somerset  and 
Worcester  counties,  Md.,  and  with  bog  ore  in  Stafford 
County,  Va.  Abundant  at  Vandreuil  in  Canada,  where  it 
is  associated  with  limonitc. 

The  blue  iron  earth  is  an  earthy  variety,  containing  about  30  per 
cent,  of  phosphoric  acid. 

Ludlamite.  A  clear  green  hydrous  phosphate  of  iron  in  monoclinic 
crystals  ;  from  Cornwall. 

Dufrenite.  A  hydrous  phosphate  of  iron  sesquioxide.  It  has  a  dull 
green  color,  and  is  often  found  in  radiated  forms. 

Cacoxenite.  Occurs  in  radiated  silky  tufts  of  a  yellow  or  yellow- 
ish-brown color.  H.  =  3-4.  G.=3P38.  •  It  is  a  phosphate  of  iron 
sesquioxide,  and  often  contains  alumina.  It  differs  from  wavellite, 
which  it  resembles,  in  its  more  yellow  color  and  iron  reactions.  It 
also  resembles  carpholite,  but  has  a  deeper  color,  and  does  not  give 
the  manganese  reactions.  It  occurs  on  brown  iron  ore  in  Bohemia. 

Clialcosideritc,  and  Andrewsite  are  other  iron  phosphates. 

Strengite.  A  hydrous  iron  phosphate  related  in  formula  to  scoro- 
dite.  From  near  Giessen. 

Ar senates  of  Iron. 

Pharmacosiderite,  or  Cube  ore.  Occurs  in  cubes  of  dark  green  to 
brown  and  red  colors.  Lustre  adamantine,  not  very  distinct.  Streak 
greenish  or  brownisTi.  H.=2'5.  G.  =3.  It  is  a  hydrous  arsenate  of 
iron  sesquioxide,  containing  43  per  cent,  of  arsenic  pentoxide.  From 
the  Cornwall  mines  ;  also  from  France  and  Saxony. 

Scorodite.  Crystallizes  in  rhombic  prisms,  with  an  angle  of  120°  10' 
between  its  secondary  prismatic  planes.  Color  pale  leek -green  or  liver 
brown.  Streak  uncolored.  Lustre  vitreous  to  subadamantine.  Sub- 
transparent  to  nearly  opaque.  H.  =  3*5-4.  G.  =3'l-3'3.  A  hydrous 
arsenate  of  iron  sesquioxide,  containing  50  per  cent,  of  arsenic  pen- 
toxide. From  Saxony,  Carinthia,  Cornwall,  and  Brazil  ;  and  minute 
crystals  near  Edenville,  N.  Y.,  with  arsenical  pyrites.  The  name  of 
this  species  is  from  the  Greek  skorodon,  garlic,  alluding  to  the  odor 
before  the  blowpipe.  Iron  sinter  is  an  amorphous  form  of  the  same 
mineral. 

Arseniosidcrite  is  another  iron  arsenate. 

Siderite.—  Spathic  Iron.     Iron  Carbonate. 

Ehombohedral.     In    rhombohedrons  with   easy  cleavage 
parallel  to  a  rhombohedron  of  107°.  Faces  often 
curved.     Usually  massive,  with  a  foliated  struc- 
ture, somewhat  curving.    Sometimes  in  globular 
concretions  or  implanted  globules. 

Color  light  grayish  to  brown;    often   dark 
brownish -red.     It  becomes  nearly  black  on  ex- 


186  DESCRIPTIONS   OF   MINERALS. 

posure.  Streak  tincolored.  Lustre  pearly  to  vitreous.  Trans* 
lucent  to  nearly  opaque.  H.  =3-4-5.  G.  =3-7-3-9. 

Composition.  Fe  03C  =  Carbon  dioxide  3 7 -9,  iron  protox- 
ide 62-1  =  100.  Often  contains  some  manganese  oxide  01 
magnesia,  and  lime  replacing  part  of  the  iron  protoxide. 
Before  the  blowpipe  it  blackens  and  becomes  magnetic  ;  but 
alone  it  is  infusible.  Dissolves  in  heated  hydrochloric  acid 
With  effervescence. 

The  ordinary  crystallized  01  foliated  variety  is  called 
spathic  or  sparry  iron,  because  the  mineral  has  the  aspect 
of  a  spar.  The  globular  concretions  found  in  some  amygda- 
loidal  rocks  have  been  called  splierosiderite  because  of  its 
spheroidal  forms.  An  argillaceous  variety  occurring  in  nod- 
ular forms  is  often  called  clay  iron  stone,  and  is  abundant 
in  coal  measures. 

Diff.  This  mineral  cleaves  like  calcite  and  dolomite,  but 
it  has  a  much  higher  specific  gravity.  It  readily  becomes 
magnetic  before  the  blowpipe.  Heated  in  a  closed  glass 
tube  it  gives  off  carbon  dioxide,  and  becomes  magnetic.  This 
test  distinguishes  it  from  other  iron  ores. 

Obs.  Spathic  iron  occurs  in  rocks  of  various  ages,  and 
often  accompanies  metallic  ores.  The  largest  deposits  are 
in  gneiss  and  mica  schist,  and  clay  slate.  It  is  also  abundant 
in  the  coal  formation  principally  in  the  form  of  clay  iron 
stone.  In  Styria  and  Carinthia,  it  is  very  abundant  in  gneiss, 
and  in  the  Hartz  it  occurs  in  graywacke.  Cornwall,  Alston- 
moor,  and  Devonshire  are  English  localities. 

A  vein  of  considerable  extent  occurs  at  Roxbury,  near 
New  Milford,  Conn.,  in  quartz,  traversing  gneiss;  "at  Ply- 
mouth, Vt.,  and  Sterling,  Mass.,  it  is  also  abundant.  It  oc- 
curs also  at  Monroe,  Conn. ;  in  New  York  State,  in  Antwerp, 
Jefferson  County,  and  in  Hermon,  St.  Lawrence  County. 
The  argillaceous  carbonate  in  nodules  and  beds,  is  very 
abundant  in  the  coal  regions  of  Pennsylvania  and  the  West. 

This  ore  is  employed  extensively  for  the  manufacture  of 
iron  and  steeL 

Mesitite  is  an  iron-and-magnesium  carbonate.  Ankerite  contains  in 
addition  a  large  percentage  of  calcium.  Like  siderite  in  crystalliza- 
tion and  cleavage. 

General  Remarks. — The  metal  iron  has  been  known  from  the  most 
remote  historical  period,  but  was  little  used  until  the  last  centuries  be- 
fore  the  Christian  era.  Bronze,  an  alloy  of  copper  and  tin,  was  the 
almost  universal  substitute,  for  cutting  instruments  as  well  as  weapons 


IRON.  187 

of  war,  among  the  ancient  Egyptians  and  earlier  Greeks  ;  and  even 
among  the  Romans  (as  proved  by  the  relics  from  Pompeii),  and  also 
throughout  Europe,  it  continued  long  to  be  extensively  employed  for 
these  purposes. 

The  Chalybes,  bordering  on  the  Black  Sea,  were  workers  in  iron  and 
steel  at  au  early  period  ;  and  near  the  year  500  B.C.,  this  metal  was 
introduced  from  that  region  into  Greece,  so  as  to  become  common  for 
weapons  of  war.  From  this  source  we  have  the  expression  chalybeate 
applied  to  certain  substances  or  waters  containing  iron. 

The  iron  mines  of  Spain  have  also  been  known  from  a  remote  epoch, 
and  it  is  supposed  that  they  have  been  worked  "  at  least  ever  since 
the  times  of  the  later  Jewish  kings ;  first  by  the  Tyrians,  next  by  the 
Carthaginians,  then  by  the  Romans,  and  lastly  by  the  natives  of  the 
country."  These  mines  are  mostly  contained  in  the  present  provinces 
of  New  Castile  and  Aragon.  Elba  was  another  region  of  ancient  works, 
"inexhaustible  in  its  iron,"  as  Pliny  states,  who  enters  somewhat  fully 
into  the  modes  of  manufacture.  The  mines  are  said  to  have  yielded 
iron  since  the  time  of  Alexander  of  Macedon.  The  ore  beds  of  Styria 
in  Lower  Austria,  were  also  a  source  of  iron  to  the  Romans. 

The  ores  from  which  the  iron  of  commerce  is  obtained,  are  the 
spathic  iron  or  carbonate,  magnetic  iron,  hematite  or  specular  iron, 
limonite  or  "brown  hematite,"  and  bog  iron  ore.  In  England,  the  prin- 
cipal ore  used  is  an  argillaceous  carbonate  of  iron,  called  often  clay 
iron  stone,  found  in  nodules  and  layers  in  the  coal  measures.  It  con- 
sists of  carbonate  of  iron,  with  some  clay,  and  externally  has  an  earthy, 
stony  look,  with  little  indication  of  the  iron  it  contains  except  in  its 
weight.  It  yields  from  20  to  35  per  cent,  of  cast  iron.  The  coal  basin 
of  South  Wales,  and  the  counties  of  Stafford,  Salop,  York,  and  Derby, 
yield  by  far  the  greater  part  of  the  English  iron.  Brown  hematite  is 
also  extensively  worked.  In  Sweden  and  Norway,  at  the  famous 
works  of  Dannemora  and  Arcndal,  the  ore  is  the  magnetic  iron  ore, 
and  is  nearly  free  from  impurities  as  it  is  quarried  out.  It  yields  50  to 
60  per  cent,  of  iron.  The  same  ore  is  worked  in  Russia,  where  it 
abounds  in  the  TJrals.  The  Elba  ore  is  the  specular  iron.  In  Germany, 
Styria,  and  Carinthia,  extensive  beds  of  the  spathic  iron  are  worked. 
The  bog  ore  is  largely  reduced  in  Prussia. 

In  the  United  States,  all  these  different  ores  are  worked.  The  local- 
ities are  already  mentioned.  The  magnetic  ore  is  reduced  in  New 
England,  New  York,  Northern  New  Jersey,  and  sparingly  in  Pennsyl- 
vania, and  other  States.  Limonite,  or  brown  hematite,  is  largely 
worked  along  Western  New  England  and  Eastern  New  York,  in  Penn- 
sylvania, and  many  States  South  and  West.  The  earthy  argillaceous 
carbonate  like  that  of  England,  and  the  hydrate,  are  found  with  the 
coal  deposits,  and  are  a  source  of  much  iron. 

The  amount  of  iron  manufactured  in  the  world  in  the  year  1873  was 
14,835,488  tons,  of  which  Great  Britain  produced  6,566,000  tons, 
United  States,  2,561,000  tons,  Germany  1,665,000  tons,  France  1,331,000 
tons,  Belgium  653,000  tons,  Austria  with  Hungary  425,000  tons,  Russia 
354,000  tons,  Sweden  322,000  tons,  Luxembourg  300,000  tons. 


188  DESCRIPTIONS   OF  MINERALS. 

MANGANESE. 

The  common  ores  of  manganese  are  the  oxides,  the  car- 
bonate, and  the  silicates.  There  are  also  sulphides,  an 
arsenide,  and  phosphate.  They  haye  a  specific  gravity  be- 
low 5  -2. 

Manganese  Sulphides  and  Arsenide, 

Aldbandite  or  Mangariblende.  A  manganese  sulphide  Mn  S,  of  an 
iron-black  color,  green  streak,  submetallic  lustre.  H.  =8*5-4  G.— 
3*9-4'0.  Crystals,  cubes  and  regular  octahedrons.  From  the  gold 
mines  of  Nagyag,  in  Transylvania. 

Hauerite.  A  sulphide,  Mn  S1',  containing  twice  the  proportion  of 
sulphur  in  the  last.  Color  reddish  brown  and  brownish  black,  re- 
sembling blende.  H.  =4.  Gr.  — 3*46.  From  Hungary. 

Kaneite  is  a  manganese  arsenide,  of  a  grayish-white  color,  and 
metallic  lustre,  which  gives  off  alliaceous  fumes.  G.=5'55.  From 
Saxony. 

Pyrolusite. — Manganese  Dioxide. 

Trimetric.  In  small  rectangular  prisms,  more  or  less 
modified.  /A/— 93°  40'.  Sometimes 
fibrous  and  radiated  or  divergent.  Of- 
ten massive  and  in  reniform  coatings. 

Color  iron-black ;  streak  black,  non- 
metallic.     H.  — 2-2-5     G.  =  4-8. 

Composition.  Mn  02  =  Manganese 
63-2,  oxygen  36 -8^100.  A  minute 
portion  of  it  imparts  to  a  borax  bead 
a  deep  amethystine  color  while  hot, 
which  becomes  red-brown  on  cooling.  It  yields  no  water 
in  a  matrass. 

Diff.  Differs  from  psilomelane  by  its  inferior  hardness, 
and  from  ores  of  iron  by  the  violet  glass  with  borax. 

Obs.  This  ore  is  extensively  worked  in  Thuringia,  Mo- 
ravia, and  Prussia.  It  is  common  in  Devonshire  and  Somer- 
setshire, in  England,  and  in  Aberdeenshire.  In  the  United 
States  it  is  associated  with  the  following  species  in  Ver- 
mont, at  Bennington,  Brandon,  Monkton,  Chittenden,  and 
Irasburg ;  it  occurs  also  in  Maine,  at  Conway,  and  Plain- 
field  in  Massachusetts  ;  at  Salisbury  and  Kent,  in  Conn., 
on  hematite  ;  on  Ked  Island,  in  the  Bay  of  San  Francisco  ; 
at  Pictou  and  Walton,  Nova  Scotia  ;  near  Bathurst,  in 
New  Brunswick. 


MANGANESE.  189 

The  name  pyrolusite  is  from  the  Greek  pur,  fire,  and  luo, 
to  wash,  and  alludes  to  its  property  of  discharging  the 
brown  and  green  tints  of  glass,  for  which  it  is  extensively 
used. 

Besides  the  use  just  alluded  to,  this  ore  is  extensively  em- 
ployed for  bleaching,  and  for  affording  the  gas  oxygen  to 
the  chemist. 

Hausmannite.  A  manganese  oxide,  2  Mn  O  +  Mn  02,  which  contains 
721  per  cent,  of  manganese,  when  pure.  Brownish  black  and  sub- 
metallic,  occurring  massive  and  in  square  octahedrons.  H.  =5-5*5. 
G.=4'7.  From  Thuringia  and  Alsatia.  Hetcerolite  is  a  zinc-hausman- 
nite,  from  Sterling  Hill,  N.  J. 

Braunite.  An  oxide  of  manganese,  containing  69  per  cent,  of  man- 
ganese  when  pure.  Color  and  streak  dark  brownish-black,  and  lustre 
submetallic.  Occurs  in  square  octahedrons  and  massive.  H.  =6-65. 
G.  =4 '8.  From  Piedmont  and  Thuringia. 

Manganite.  A  hydrous  sesquioxide  of  manganese.  Occurs  massive 
and  in  rhombic  prisms.  Color  steel-black  to  iron-black.  H.=4-4'5. 
G.  :=4-3-4-4.  From  the  Hartz,  Bohemia,  Saxony,  and  Aberdeenshire. 
It  is  found  at  several  points  in  New  Brunswick  and  Nova  Scotia. 


Psilomelane. 

Massive  and  botryoidal.  Color  black  or  greenish-black. 
Streak  reddish  or  brownish-black,  shining.  H.  =5-6.  G.= 
4-4-4. 

Composition.  Essentially  manganese  dioxide  with  a  little 
water,  and  also  some  baryta  or  potassa.  The  compound  is 
somewhat  varying  in  its  constitution.  Before  the  blowpipe 
like  pyrolusifce,  except  that  it  affords  water. 

Obs.  This  is  an  abundant  ore,  and  is  associated  usually 
with  the  pyrolusite.  It  occurs  at  the  different  localities 
mentioned  under  pyrolusite,  and  the  two  are  often  in  alter- 
nating layers  ;  it  has  been  considered  an  impure  variety  of 
the  pyrolusite.  The  name  is  from  the  Greek  psilos,  smooth 
or  naked,  and  melas,  black. 

Pyrochroite.  Hydrous  manganese  protoxide,  of  white  color.  From 
Sweden.  MnO2H,. 

Pdugite.  The  manganese  nodules  found  in  many  regions  over  the 
bottom  of  the  ocean.  Affords,  according  to  an  analysis,  about  40  per 
cent,  of  MnOo,  27  ffe03,  l:j  of  water  lost  at  a  red  heat,  along  with  14 
per  cent,  of  silica  and  4  of  alumina  ;  24'5  per  cent,  of  water  were 
lost  below  100°  C.  Probably  a  mixture. 

Ghalcophanite.  A  hydrous  oxide  of  manganese  and  zinc,  in  rhombo- 
hedral  crystals  and  stalactites  ;  from  Sterling  Hill,  N.  J. 


190  DESCRIPTIONS   OF   MINERALS. 


Wad. — Bog  Manganese. 

Massive,  reniform  or  earthy  ;  also  in  coatings  and  dendri- 
tic delineations.  Color  and  streak  black  or  brownish  black. 
Lustre  dull,  earthy.  H.  =  l-6.  G.  — 3-4.  Soils  the  fingers. 

Composition.  Consists  of  manganese  dioxide,  in  varying 
proportions,  from  30  to  70  per  cent.,  mechanically  mixed 
with  more  or  less  of  iron  sesquioxide;  10  to  25  per  cent,  of 
water,  and  often  several  per  cent,  of  oxide  of  cobalt  or  cop- 
per. It  is  formed  in  low  places  from  the  decomposition  of 
minerals  containing  manganese.  Gives  off  much  water 
when  heated,  and  affords  a  violet  glass  with  borax. 

Obs.  Wad  is  abundant  in  Columbia  and  Dutchess  coun- 
ties, N.  Y.,  at  Austerlitz,  Canaan  Centre,  and  elsewhere; 
also  at  Blue  Hill  Bay,  Dover,  and  other  places  in  Maine ; 
at  Nelson,  Gilmanton,  and  Grafton,  N.  H.;  and  in  many 
other  parts  of  the  country. 

It  may  be  employed  like  the  preceding  in  bleaching,  but 
is  too  impure  to  afford  good  oxygen.  It  may  also  be  used 
for  umber  paint. 

Lampadite,  or  Cupreous  Manganese.  A  wad  containing  4  to  18  per 
cent,  of  copper  oxide. 

Triphylite. 

Trimetric.  In  rhombic  crystals,  massive.  Color  green- 
ish gray  to  bluish  gray,  but  often  brownish  hlack  externally 
from  the  oxidation  of  the  manganese  present.  Streak 
grayish  white.  Lustre  subresinous.  H.  =5.  G.  =3  "54-3 '6. 

Composition,  (JLi2  f  R)3  08  P2,  in  which  R  stands  for  Fe 
and  Mn.  A  Bodenmais  specimen  afforded  Phosphorus 
pentoxide  44*19,  iron  protoxide  38*21,  manganese  protoxide 
5-63,  magnesia  2-39,  lime  0'76,  lithia  7 '69,  soda  0'74,  pot- 
ash 0-04,  silica  0  -40= 100-05.  B.B.  fuses  very  easily,  color- 
ing the  flame  a  beautiful  red,  in  streaks,  with  a  pale  bluish- 
green  on  the  exterior  of  the  flame.  Soluble  in  hydrochloric 
acid. 

Obs.  Found  at  Rabenstein  in  Bavaria ;  in  Finland  ;  at 
Norwich,  Mass. ;  Grafton,  N.  H. 

LitMophilite,  A  salmon-colored  manganese-lithium  phospliate,  al. 
lied  in  composition  to  triphylite,  but  containing  very  little  iroa 
From  Redding  (near  Branchville  Depot),  Conn. 


MANGANESE.  J^l 

Triplite. 

Trimetric.  Usually  massive,  with  cleavage  in  three  di- 
rections. Color  blackish  brown.  Streak  yellowish  gray. 
Lustre  resinous  ;  nearly  or  quite  opaque.  H.=5-5-5  G  = 
3-4-38. 

Composition.  (Mn,Fe)308P2  +  RF2,  affording  about  30 
per  cent,  of  manganese  protoxide,  8  of  fluorine.  Fuses 
easily  to  a  black  magnetic  globule.  B.B.  imparts  a  violet 
color  to  the  hot  borax  bead.  Dissolves  in  hydrochloric 
acid. 

Obs.  From  Limoges  in  France.  Rather  abundant  at 
Washington,  Conn.,  and  sparingly  found  at  Sterling,  Mass. 

Heterosite,  Alluaudite,  Pseudotriplite,  are  regarded  as  results  of 
alteration,  either  of  triphyline  or  of  triplite. 

Triploidite.  A  manganese-iron  phosphate  like  triplite,  but  having 
the  fluorine  replaced  by  the  elements  of  water.  From  Redding,  Conn. 

Dickinsonite.  An  oil-green  to  olive-green  manganese-iron-calcium 
phosphate.  From  Redding,  Conn. 

Reddingite.  A  rose-pink  hydrous  manganese-iron  phosphate.  Mn, 
Oe  P2  +  3  aq,  isomorphous  with  scorodite  and  strengite.  Redding,  Ct. 

Fairfieldite,  hydrous  manganese-calcium  phosphate.     Ibid. 

Hureaulite.  Rose-colored  to  brownish-orange  hydrous  manganese- 
iron  phosphate.  From  Hureaux,  France. 

Rhodochrosite.— Manganese  Carbonate. 

Rhombohedral.  E  A  12=  166°  51';  like  calcite  in  hav- 
ing three  easy  cleavages,  and  in  lustre.  Color  rose-red. 
H.  =3-5-4-5.  G.  =  3'4-3-7. 

Composition.  Mn  03  C  =  Carbonic  acid  386,  manganese 
protoxide  61 '4=100.  Part  of  the  manganese  often  replaced 
by  calcium,  magnesium  or  iron. 

Obs.  From  Saxony,  Transylvania,  the  Hartz,  Ireland ; 
Mine  Hill,  New  Jersey  ;  Redding,  Conn. ;  Austin,  Nevada  ; 
Placentia  Bay,  Newfoundland. 

Rhodonite.     A  manganese  silicate.     See  p.  247 

General  Remarks.  Manganese  is  never  used  in  the  arts  in  the  pure 
state  ;  but  as  an  oxide  it  is  largely  employed  in  bleaching.  The  im- 
portance of  the  ore  for  this  purpose  depends  on  the  oxygen  it  con- 
tains, and  the  facility  with  which  this  gas  is  given  up.  As  the  ores 
are  often  impure,  it  is  important  to  ascertain  their  value  in  this  re- 
spect. This  is  most  readily  done  by  heating  gently  the  pulverized  ore 
with  hydrochloric  acid,  and  ascertaining  the  amount  of  chlorine  given 
off.  The  chlorine  may  be  made  to  pass  into  milk  of  lime,  to  form  a 
chloride,  and  the  value  of  the  chloride  then  tested  according  to  the 
usual  modes.  The  amount  of  chlorine  derived  from  a  given  quantity 


DESCRIPTIONS   OF   MINERALS. 

of  muriatic  acid  depends  not  only  on  the  amount  of  oxygen  in  the  ore, 
but  also  on  the  presence  or  absence  of  baryta  and  such  other  earths  as 
may  combine  with  this  acid.  The  binoxide  of  manganese,  when  pure, 
affords  18  parts  by  weight  of  chlorine,  to  22  parts  of  the  oxide  ;  or  23^ 
cubic  inches  of  gas  from  22  grains  of  the  oxide.  The  best  ore  should 
give  about  three-fourths  its  weight  of  chlorine,  or  about  7,000  cubic 
inches  to  the  pound  avoirdupois. 

Iron  ores  containing  some  manganese  are  used  for  making  spiegeleisen, 
a  hard  highly  crystallized  pig-iron,  containing  a  large  amount  of  car- 
bon and  some  manganese.  A  manganesian  iron  carbonate  or  siderite  is 
thus  used,  and  also  the  franklinite  of  New  Jersey. 

Manganese  is  also  employed  to  give  a  violet  color  to  glass.  The 
sulphate  and  the  chloride  of  manganese  are  used  in  calico  printing. 
The  sulphate  gives  a  chocolate  or  bronze  color. 

ALUMINUM. 

The  aluminum  compounds  among  minerals  include  only 
one  oxide — a  sesquioxide  =41  03 — hydrated  oxides,  fluorides, 
and,  among  ternaries,  sulphates,  phosphates,  and  numerous 
silicates.  There  are  no  sulphides  or  arsenides,  and  no  car- 
bonate, with  a  single  imperfectly  understood  exception. 

The  silicates  are  described  in  the  following  section.  Many 
aluminum  compounds  may  be  distinguished  by  means  of  a 
blowpipe  experiment,  as  explained  011  page  87. 

Corundum. 

Rhombohedral.    R  A  R  or  r  A  r=8G°  4'.     Cleavage  some- 
times perfect  parallel  with  0,  and  sometimes  par- 
allel to  the  rhombohedral  faces.    Usual  in  six- 
sided  prisms,  often  with  uneven  surfaces,  and 
sometimes  so  irregular  that  the  form  is  scarcely 
traceable.     Occurs  also  granular.     Colors  blue, 
and  grayish-blue  most  common  ;  also  red,  yel- 
low,  brown,   and   nearly  black  ;  often   bright. 
When  polished  on  the  surface  0,  a  star  of  six 
rays,  corresponding  with  the  six-sided  form  of 
the  prism,  is  sometimes  seen  within  the  crystal. 
Transparent  to   translucent.     H.  =  9,    or   next   below   the 
diamond.  Exceedingly  tough  when  compact.   G.  =3*9-4*16. 
Composition.    A103= Oxygen  46-8,  aluminum  53-2  =  100; 
pure  alumina.    B.B.  remains  unaltered  both  alone  and  with 
soda.     The. fine  powder  moistened  with  cobalt  nitrate  and 
ignited  assumes  a  blue  color. 


COMPOUNDS   OF   ALUMINUM.  193 

VARIETIES.  The  name  sapphire  is  usually  restricted,  in 
common  language,  to  clear  crystals  of  bright  colors,  used  as 
gems  ;  while  dull,  dingy-colored  crystals  and  masses  are 
called  corundum,  and  the  granular  variety  of  bluish-gray 
and  blackish  colors  containing  much  disseminated  magne- 
tite (whence  its  dark  color)  is  called  emery. 

Blue  is  the  true  sapphire  color.  When  of  other  bright 
tints,  it  receives  other  names ;  as  oriental  ruby,  when  red  ; 
oriental  topaz,  when  yellow  ;  oriental  emerald,  when  green  ; 
oriental  amethyst,  when  violet,  and  adamantine  spar,  when 
hair-brown.  Crystals  with  a  radiate  chatoyant  interior  are 
often  very  beautiful,  and  are  called  asteria,  or  asteriated 
mppliire. 

Diff.  Distinguished  readily  by  its  hardness,  exceeding  all 
species  except  the  diamond,  and  scratching  quartz  crystals 
with  great  facility. 

Obs.  The  sapphire  is  often  found  loose  in  the  soil.  Meta- 
morphic  rocks,  especially  gneissoid  mica  schist,  and  granu- 
lar limestone,  appear  to  be  its  usual  matrix.  It  is  met  with 
in  several  localities  in  the  United  States,  but  seldom  suffi- 
ciently fine  for  a  gem.  A  blue  variety  occurs  at  Newton, 
K  J.,  in  crystals  sometimes  several  inches  long  ;  bluish  and 
pink,  at  Warwick,  N.  Y.;  white,  blue,  and  reddish  crystals 
at  Amity,  N.  Y. ;  grayish,  in  large  crystals,  in  Delaware 
and  Chester  counties,  Pennsylvania  ;  pale  blue  crystals 
have  been  found  in  bowlders  at  West  Farms  and  Litchfield, 
Conn.  It  occurs  also  in  large  quantities  in  North  Carolina, 
where  crystals  are  numerous  though  rarely  fit  for  jewelry, 
and  where  one  has  been  obtained  weighing  312  pounds,  and 
having  a  reddish  color  outside  and  bluish-gray  within  ;  also 
in  Cherokee  County,  Georgia  ;  in  Los  Angeles  County,  Cali- 
fornia. Emery  is  mined  at  Chester,  in  Mass. 

The  principal  foreign  localities  are  as  follows  :  blue,  from 
Ceylon  ;  the  finest  red  from  the  Capelan  Mountains  in  the 
kingdom  of  Ava,  and  smaller  crystals  from  Saxony,  Bohemia 
and  Auvergne  ;  corundum,  from  the  Carnatic,  on  the  Mala- 
bar coast,  and  elsewhere  in.  the  East  Indies  ;  adamantine 
spar,  from  the  Malabar  coast  ;  emery,  in  large  bowlders 
from  near  Smyrna,  and  also  at  Naxos  and  several  of  the 
Grecian  islands. 

The  name  sapphire  is  from  the  Greek  word  sapplieiros, 
the  name  of  a  blue  gem.  It  is  doubted  whether  it  included 
the  sapphire  of  the  present  day. 


194  DESCRIPTIONS   OF   MINERALS. 

Next  to  the  diamond,  the  sapphire  in  some  of  its  varieties 
is  the  most  costly  of  gems.  The  red  sapphire  is  much  more 
highly  esteemed  than  those  of  other  colors.  A  crystal  of 
one,  two  or  three  carats  is  valued  at  the  price  of  a  diamond 
of  the  same  size.  They  seldom  exceed  half  an  inch  in  their 
dimensions.  Two  splendid  red  crystals,  as  long  as  the  little 
finger  and  about  an  inch  in  diameter,  are  said  to  be  in  the 
possession  of  the  king  of  Arracan.  The  largest  oriental  ruby 
known  was  brought  from  China  to  Prince  Gargarin,  gov- 
ernor of  Siberia  ;  it  afterward  came  into  the  possession  of 
Prince  Menzikoff,  and  constitutes  now  a  jewel  in  the  im- 
perial crown  of  Russia. 

Blue  sapphires  occur  of  much  larger  size.  According  to 
Milan,  Sir  Abram  Hume  possessed  a  crystal  which  was  three 
inches  long.  One  of  9-51  carats  is  stated  to  have  been  found 
in  Ava. 

Corundum  and  emery  are  crushed  to  a  powder  of  differ- 
ent degrees  of  fineness,  and  make  the  abrading  and  polishing 
jpiaterial  called  in  the  shops  emery.  The  iron  oxide  of  true 
emery  diminishes  its  hardness,  and  consequently  its  abrasive 
power  ;  pulverized  corundum  is  more  valuable  and  efficient 
in  abrasion. 

Diaspore.  Hydrated  aluminum  of  the  formula  Al  O4  H2= Water  14 '9, 
alumina  85 '1=100.  Usually  found  assotiated  with  corundum.  Crys- 
tals usually  thin  and  flattened.  Color  whitish,  grayish,  pinkish,  etc. 
Very  brittle.  Translucent.  H.  6 '5-7.  G.  3 '5.  From  the  Urals  ; 
Schemnitz  ;  Chester,  Mass. ;  Chester  County,  Pa. ;  North  Carolina. 
<  Gibbsite  (Hydrargillite).  Hydrated  alumina  ;  Al  06  H«= water  34 '5, 
alumina  65*5=100.  Occurs  in  hexagonal  crystals  ;  more  commonly  in 
stalactitic  aiad  mammillary  forms,  with  smooth  surface,  looking  like 
chalcedony.  Color  white,  grayish  and  greenish -white  ;  translucent, 
sometimes  transparent  when  in  crystals.  H.  =2'5-3'5;  G.=2'3-2*4. 
Near  Slatoust  in  the  Ural  ;  in  Asia  Minor  ;  on  corundum  at  Unionville, 
Pa. ;  at  Richmond,  Mass,  in  stalactitic  forms  ;  in  Orange  County,  N.  Y. 

Hydrotalcite  ( Volknerite,  Houghite).  A  soft  pearly  mineral,  contain- 
ing alumina,  magnesia,  and  water.  Accompanies  spinel,  and  some- 
times a  result  of  the  alteration  of  spinel  crystals.  Occurs  near  Sla- 
toust ;  at  Snarum,  Norway  ;  near  Oxbow  in  Rossie,  St.  Lawrence 
County,  N.  Y.  (the  variety  Houghite}. 

Spinel. 

Isometric.  In  octahedrons,  more  or  less  modified.  Fig- 
ure 4  represents  a  -  twin  crystal.  Occurs  only  in  crystals  ; 
cleavage  octahedral,  but  difficult. 

Color  red,  passing  into  blue,  green,  yellow,  brown,  and 


.COMPOUNDS    OF    ALUMINUM. 


195 


black.  The  red  shades  often  transparent  and  bright ;  the 
dark  shades  usually  opaque.  Lustre  vitreous.  II.  =8. 
G.=3-5-4'l. 


2. 


4. 


Composition.  MgAl  04=Mg  0  -f-  A103= Alumina  72,  mag- 
nesia 28  =  100.  The  aluminum  is  sometimes  replaced  in 
part  by  iron,  and  the  magnesium  often  in  part  by  iron,  cal- 
cium, manganese  and  zinc.  Infusible  ;  insoluble  in  acids. 

VARIETIES.  The  following  varieties  of  this  species  have 
received  distinct  names  :  the  scarlet  or  bright  red  crys- 
tals, spinel  ruby  ;  the  rose-red,  balas-ruby  ;  the  orange-red, 
rubicelle;  the  violet,  almandine-ruby  ;  the  green,  cliloro- 
spinel ;  while  the  black  varieties  are  called  pleonaste.  Pleo- 
naste  crystals  contain  sometimes  8  to  20  percent,  of  oxide 
of  iron.  Picotite  is  a  variety  containing  7  per  cent,  of 
chromium  oxide. 

Diff.  The  form  of  the  crystals  and  their  hardness  dis- 
tinguish the  species.  Garnet  is  fusible.  Magnetite  is  at- 
tracted by  the  magnet.  Zircon  has  a  higher  specific  gravity 
and  is  not  so  hard.  The  red  crystals  often  resemble  the 
true  ruby  (red  corundum),  but  the  latter  are  never  in  octa- 
hedrons. 

Obs.  Occurs  in  granular  limestone  ;  also  in  gneiss  and 
volcanic  rocks.  At  numerous  places  in  the  adjoining  coun- 
ties of  Sussex  in  New  Jersey,  and  Orange  county,  of  various 


19C  DESCRIPTIONS   OF   MINERALS. 

colors  from  red  to  brown  and  black ;  especially  at  Frank- 
lin, Newton  and  Sparta,  in  the  former,  and  in  Warwick, 
Amity  and  Edenville,  in  the  latter.  The  crystals  are  octa- 
hedrons, and  often  grouped  or  disseminated  singly  in  gran- 
ular limestone.  One  crystal,  found  at  Amity  by  Dr.  Heron, 
weighs  49  pounds.  The  limestone  quarries  of  Bolton,  Box- 
borough,  Chelmsford  and  Littleton,  Mass.,  afford  a  few 
crystals. 

Crystals  of  spinel  are  occasionally  soft,  having  under- 
gone a  change  of  composition  approaching  steatite  in  all 
characters  except  form.  They  are  true  pseudomorplis.  They 
are  met  with  in  Sussex  and  Orange  counties.  Other  spinel 
pseudomorplis  consist  of  hydrotalcite  (see  preceding  page). 

Uses.  The  fine  colored  spinels  are  much  used  as  gems. 
The  red  is  the' common  ruby  of  jewelry,  the  oriental  rubies 
being  sapphire. 

Gahnite  is  a  spinel  in  which  zinc  takes  the  place  of  part  or  all  of  the 
magnesium;  when  all,  it  is  called  Automolite.  Color  dark  green  or  green- 
ish black.  H.  =7-5-8.  G.— 4-4-6.  When  fused  with  sufficient  soda, 
B.B.  on  coal  a  white  coat  of  zinc  oxide  is  deposited,  which  is  yellow 
when  hot.  B.B.  infusible.  At  Franklin,  N.  J.,  and  at  the  Canton 
mine  in  Georgia.  Occurs  in  granite  at  Haddam  with  beryl,  chryso- 
beryl, garnet,  etc.  In  Sweden,  near  Fahlun,  in  talcose  slate. 

Dysluite.  A  variety  of  gahnite  containing  oxide  of  manganese. 
Color  yellowish  or  grayish-brown.  H.r=7'5-8.  G.=4'55.  Composi- 
tion, Alumina  30'5,  zinc  oxide  16'8,  iron  sesquioxide  41 '9,  manganese 
protoxide  7 '6,  silica  3,  water  0'4.  From  Sterling,  N.  J.,  with  frank- 
linite  and  troostite. 

Kreittonite  is  a  zinc-iron  gahnite. 

Hercinite  is  a  spinel  affording  on  analysis  alumina  and  iron  protoxide, 
with  only  2 '9  per  cent,  of  magnesia. 

Chrysoberyl. 

Trimetric.  /A 7=129°  38'.  Also  in  compound  crystals, 
as  in  fig.  2.  Crystals  sometimes  thick  ;  often  tabular. 

Color  bright  green,  from  a  light  shade  to  emerald-green  ; 
rarely  rasptierry  or  columbine-red  by  transmitted  light. 
Streak  uncolored.  Lustre  vitreous.  Transparent  to  trans- 
lucent, H.  =  8'5.  G.  =3-5-3 -8. 

Composition.  Be  Al  04  =  Alumina  80 -2,  glucina  19;8  =  100. 
A  little  iron  is  sometimes  present.  B.B.  infusible  and  un- 
altered. 

Alexandrite  is  an  emerald-green  variety  from  the  Urals, 
colored  by  chrome,  bearing  the  same  relation  to  ordinary 
chrysoberyl  as  emerald  to  beryl.  Fig.  7  is  of  this  variety. 


COMPOUNDS   OF   ALUMINUM. 


197 


Diff.  Near  beryl,  but  distinct  in  not  being  regularly  hex- 
agonal in  crystallization. 

Obs.  Chrysoberyl  occurs  in  the  United  States  in  granite 
at  Haddam,  Conn.,  and  Greenfield,  near  Saratoga,  N.  Y., 
associated  with  beryl,  garnet,  etc. ;  in  Norway,  Maine. 


1. 


The  name  chrysoberyl  is  from  the  Greek  chrysos,  golden, 
and  beryllos,  beryl. 

The  crystals  are  seldom  sufficiently  pellucid  and  clear 
from  flaws  to  be  valued  in  jewelry  ;  but  when  of  fine  qual- 
ity, it  forms  a  beautiful  gem,  and  is  often  opalescent. 

Fluorides  of  Aluminum. 

Cryolite.  In  snow-white  masses,  having  rectangular  cleavages,  and 
remarkable  for  melting  easily  in  the  flame  of  a  candle,  to  which  its 
name  (from  the  Greek  kruos,  ice)  alludes.  H.=2-o.  G.=2'95.  It  is 
a  sodium-aluminum  fluoride.  Prom  Greenland. 

Chiolite  and  Chodnefflte  are  near  cryolite  in  composition  and  charac- 
ters. Arksutite,  Gearksutite,  Pachnolite,  Thomsenolite  are  related  fluor- 
ine compounds  which  occur  associated  with  the  Greenland  cryolite. 
From  Siberia. 

Fluellite.  From  Cornwall,  in  minute  white  rhombic  octahedrons. 
Contains  fluorine  and  aluminum. 

Alunogen.— Hydrous  Aluminum  Sulphate. 

In  silky  efflorescences,  and  crusts  of  a  white  color,  having 
a  taste  like  common  alum.  H.  —1-5-2.  G.  =1-6-1  '8. 

Composition.  Al  0,2  S3  4-  ISaq  =  Sulphur  trioxide  36-0, 
alumina  15-4,  water  48-0  =  100. 

Obs.  A  common  efflorescence  in  solfataras  of  volcanic 
regions,  and  also  often  occurring  in  shales  of  coal  regions 
and  other  rocks  containing  pyrite  ;  the  oxidation  of  the 
pyrite — an  iron  sulphide — affords  sulphuric  acid,  which 
acid  combines  with*  the  alumina  of  the  shale. 


198  DESCRIPTIONS   OF  MINERALS?. 

.  Alums  Frequently  the  sulphuric  acid  resulting  from  the  oxidation 
of  a  sulphide,  or  in  some  other  way,  combines  also  with  the  iron, 
magnesia  or  potash  or  soda  of  the  shale  or  other  rock,  as  well  as  the 
alumina,  and  so  makes  other  kinds  of  aluminum  sulphate. 

Combining  thus  with  potash  it  produces  common  alum  called  Kali- 
nite  or  potash  alum,  whose  formula  is  K2A13  02<  S4  +  18  aq  ;  with  am- 
monia, it  forms  an  ammonia-alum,  named  Tschermigite ;  with  iron, 
iron  alum,  called  Halotrichite ;  with  soda,  a  soda-alum,  Mendozite ; 
with  magnesia  a  magnesia-alum,  Pickeringite ;  with  manganese,  a 
manganese-alum,  Apjohnile  and  Bosjemanite.  The  formulas  of  these 
alums  are  alike  in  atomic  proportions,  excepting  in  the  amount  of 
water,  which  varies  from  18  aq  to  24  aq. 

Shale  containing  alunogen  or  any  of  the  alums  is  often  called  alum 
shale.  Such  rocks,  whether  shales  or  of  other  kinds,  are  often  quar- 
ried and  lixiviated  for  the  alum  they  contain  or  will  afford.  The  rock 
is  first  slowly  heated  after  piling  it  in  heaps,  in  order  to  decompose 
the  remaining  pyrites  and  transfer  the  sulphuric  acid  of  any  iron  sul- 
phate to  the  alumina  and  thus  produce  the  largest  amount  possible  of 
aluminum  sulphate.  It  is  next  lixiviated  in  stone  cisterns.  The  lye 
containing  this  sulphate  is  afterwards  concentrated  by  evaporation, 
and  then  the  requisite  proportion  of  potassium  in  the  form  of  the  sul- 
phate or  chloride  is  added  to  the  hot  solution.  On  cooling,  the  alum 
crystallizes  out,  and  is  afterwards  washed  and  re-crystallized.  The 
mother  liquor  left  after  the  precipitation  is  revaporated  to  obtain  the 
remaining  alum  held  in  solution.  This  process  is  carried  on  exten- 
sively in  Germany,  France,  at  Whitby  in  Yorkshire,  Hurlett  and 
Campsie,  near  Glasgow,  in  Scotland.  Cape  Sable  in  Maryland  affords 
large  quantities  of  alum  annually.  The  slates  of  coal  beds  are  often 
used  to  advantage  in  this  manufacture,  owing  to  the  decomposing 
pyrites  present.  At  Whitby,  130  tons  of  calcined  schist  give  one  ton 
of  alum.  In  France,  ammoniacal  salts  are  used  instead  of  potash, 
and  an  ammonia  alum  is  formed. 

Alum  is  also  manufactured  from  cryolite  (see  p.  197),  which  is  ob- 
tained from  Greenland. 

Alunite. — Alum  Stone. 

Rhombohedral,  with  perfect  basal  cleavage*.  Also  mas- 
sive. Color  white,  grayish,  or  reddish.  Lustre  of  crystals 
vitreous,  or  a  little  pearly  on  the  basal  plane.  Transparent 
to  translucent.  H.  =4.  G.  =  2-5S-2'75. 

Composition.  K2  Al  022  S4-fG  aq=  Sulphuric  trioxide  38*5, 
alumina  371,  potash  11'4,  water  13-0^100.  B.B.  decrepi- 
tates and  is  infusible  ;  gives  reaction  for  sulphur. 

Diff.  Distinguished  by  its  infusibility,  in  connection  with 
its  complete  solubility  in  sulphuric  acid  without  forming  a 
jelly- 

Obs.  Found  in  rocks  of  volcanic  origin  at  Tolfa,  near 
Rome  ;  and  also  at  Beregh  and  elsewhere  in  Hungary. 

When  it  is  calcined  the  sulphates  become  soluble,  and  the 


COMPOUNDS  OF  ALUMINUM.  199 

alum  is  dissolved  out.  On  evaporation  the  alum  crystallizes 
from  the  fluid  in  cubic  crystals.  This  is  called  Roman  alum, 
and  is  highly  valued  by  dyers,  because,  although  the  crystals 
are  colored  red  by  iron  oxide,  no  iron  is  chemically  com- 
bined with  the  salt  as  is  usual  in  common  alum. 

Aluminite  (Webstcrite).  Another  hydrous  aluminum  sulphate,  in 
compact  reniform  masses,  and  tasteless.  From  New  Haven,  in  Sussex  ; 
Epernay,  in  France  ;  and  Halle,  in  Prussia. 

Lcewiyite  is  a  potassium-aluminum  sulphate,  containing  half  the 
water  of  potash  alum. 

Ambly gonite.  — Lithium- Aluminum  Phosphate. 

Triclinic,  with  cleavages  unequal  in  two  directions,  mak- 
ing an  angle  with  one  another  of  104£°.  Lustre  vitreous 
to  pearly  and  greasy.  Color  pale  mountain-green,  or  sea- 
green  to  white.  Translucent  to  subtransparent.  H.  =  6. 
G.=  3-3-11. 

Composition.  A  lithium-aluminum  phosphate,  Al  OgP2  + 
1£  (Li,  Na)  F.  B.B.  fuses  very  easily  with  intumescence, 
coloring  the  flame  yellowish  red  to  rich  carmine-red,  owing 
to  the  lithia  present,  and  traces  of  green  owing  to  the  phos- 
phoric acid.  Gives  the  reaction  also  for  fluorine. 

Obs.   Occurs  in  Saxony  and  Norway. 

HebroniU  is  a  closely  related  mineral  from  Hebron  and  Mount  Mica 
in  Maine,  and  from  Redding  in  Connecticut. 

Herderite  is  supposed  to  be  an  anhydrous  calcium-aluminum  phos- 
phate with  fluorine. 

Durangite.  An  anhydrous  arsenate  of  an  orange-red  color,  contain- 
ing aluminum,  sodium,  iron,  and  some  manganese,  with  over  7  per 
cent,  of  fluorine.  From  Durango,  Mexico,  where  it  occurs  with  cas- 
siterite  or  tin  ore. 

Lazulite. 

Monoclinic.  In  crystals  and  also  massive,  of  an  azure-blue 
color.  H.=5-6.  G.  =  3'057. 

Composition.  RA1  09  P2  4-  aq= Phosphorus  pentoxide  46'  8, 
alumina  34'0,  magnesia  13-2,  water  6 '0=100.  B.B.  in  the 
closed  tube  whitens  and  yields  water  ;  with  cobalt  solution 
the  color  is  restored;  in  the  forceps  whitens,  swells,  cracks, 
and  falls  to  pieces  without  fusion,  coloring  the  flame  bluish- 
green. 

Obs.  From  Salzburg,  Styria;  \Vermland,  Sweden;  Crowder 
Mount,  Lincoln  County,  JNT.  C.  ;  and  on  Graves  Mountain, 
Lincoln  County,  Georgia. 


200  DESCRIPTIONS   OF   MINERALS. 


Variscite  (Peganite,  Callainite)  is  another  hydrous  aluminum  phos- 
phate ;  it  is  of  a  light  green  color,  of  various  shades,  to  deep  emerald- 
green.  From  Montgomery  County,  Arkansas,  and  from  Colorado  ;  also 
from  Messbach,  in  Saxon  Voigtland.  Fischerite,  is  a  related  mineral. 

Turquois. 

In  opaque  reniform  masses  without  cleavage;  of  a  bluish- 
green  color,  and  somewhat  waxy  lustre.  II.  — 6.  G.  — 2-6 

2»Q 
O. 

Composition.  Phosphorus  pentoxide  32  *G,  alumina  46*9, 
water  20*5  =  100.  13.  B.  infusible,  but  becomes  brown  and 
colors  the  flame  green  ;  soluble  in  hydrochloric  acid  ;  moist- 
ened with  the  acid  it  gives  a  momentary  bluish  green  color 
to  the  flame,  owing  to  the  copper  that  it  contains. 

Diff.  Distinguished  from  bluish-green  feldspar,  which  it 
resembles,  by  its  infusibility  and  the  reactions  for  phos- 
phorus. 

Obs.  Turquois  is  brought  from  a  mountainous  district  in 
Persia,  not  far  from  Nichabour  ;  and,  according  to  Agaphi, 
occurs  in  veins  that  traverse  the  mountain  in  every  direc- 
tion. 

The  Callais  of  Pliny  was  probably  turquois.  Pliny,  in 
his  description  of  it,  mentions  the  fable  that  it  was  found 
in  Asia,  projecting  from  the  surface  of  inaccessible  rocks, 
whence  it  was  obtained  by  means  of  slings. 

Turquois  receives  a  fine  polish  and  is  highly  esteemed  as 
a  gem.  In  Persia  it  is  much  admired,  and  the  Persian 
king  is  said  to  retain  for  himself  all  the  large  and  more 
finely  tinted  specimens.  The  occidental  or  lone  turquois, 
is  fossil  teeth  or  bones,  colored  with  a  little  phosphate  of 
iron.  Green  malachite  is  sometimes  substituted  for  turquois, 
but  it  is  of  little  hardness  and  has  a  different  tint  of  color. 
The  stone  is  so  well  imitated  by  art  as  scarcely  to  be  detected 
except  by  chemical  tests.  The  imitation  is  much  softer 
than  true  turquois. 

Childrenite.  A  hydrous  phosphate  containing  aluminum,  iron,  with 
little  manganese.  Found  in  trimetric  crystals  in  Devonshire  and 
Cornwall  ;  also  at  Hebron  in  Maine. 

Eosphorite.  Has  the  crystalline  form  and  nearly  the  angles  of  chil- 
drenite,  and  contains  the  same  constituents,  but  differs  in  being 
essentially  a  hydrous  phosphate  of  manganese  with  little  iron.  From 
Bedding,  Connecticut. 

Henwoodite  is  a  hydrous  aluminum  phosphate  from  Cornwall,  con- 
taining also  copper. 


COMPOUNDS  OF  CERIUM,  YTTRIUM,  LANTHANUM.      201 

Wavellite. 

Trimetric.  Usually  in  small  hemispheres  a  third  or  half 
an  inch  across,  attached  to  the 
surface  of  rocks,  and  having  a 
finely  radiated  structure  within  ; 
when  broken  off  they  leave  a  stel- 
late circle  on  the  rock.  Some- 
times in  rhombic  crystals. 

Color  white,  green,  or  yellowish  and  brownish,  with  a 
somewhat  pearly  or  resinous  lustre.  Sometimes  gray  or 
black.  Translucent.  H.  =3*5-4.  G.  =  2*3.  .  • 

Composition.  Al3Oi9P4  +  12aq  =  Phosphorus  pentoxide 
35-16,  alumina  38-10,  water  26  74  =  100.  1  to  2  per  cent, 
of  fluorine  is  often  present,  replacing  the  oxygen.  B.B. 
whitens  and  swells,  but  does  not  fuse.  Colors  the  flame 
green,  especially  if  previously  moistened  with  sulphuric 
acid.  Moistened  with  cobalt  nitrate,  assumes  a  blue  color 
after  ignition  ;  gives  much  water  in  the  closed  glass  tube. 

Diff.  Distinguished  from  the  zeolites,  some  of  which  it 
resembles,  by  giving  the  reaction  of  phosphorus,  and  also 
by  dissolving  in  acids  without  gelatinizing.  Cacoxene,  to 
which  it  is  allied,  becomes  dark  reddish-brown  before  the 
blowpipe,  and  does  not  give  the  blue  with  cobalt  nitrate. 

Obs.  Occurs  at  the  slate  quarries  of  York  County,  Pa., 
and  also  at  Washington  Mine,  Davidson  County,  N.  C. ;  at 
Magnet  Cove,  Ark.  It  was  first  discovered  by  Dr.  Wavel, 
in  clay  slate  in  Devonshire.  Occurs  also  in  Bohemia  and 
Bavaria. 

Zepliaromchite  is  near  wavellite. 

Mellite  or  Hon^y  stone.  In  square  octahedrons,  looking  like  a  honey, 
yellow  resin  ;  may  be  cut  with  a  knife.  It  is  an  aluminum  mellate. 
Found  in  Tkuringia,  Bohemia,  Moravia,  etc. 

Dawsonite.  Hydrous  aluminum-calcium  carbonate,  from  a  felsyte 
dike  near  Montreal. 


CERIUM,  YTTRIUM,  ERBIUM,  LANTHANUM,  DIDYMIUM. 

Known  in  nature  in  the  condition  of  fluorides,  tantalates, 
columbates,  phosphates,  or  carbonates,  and  also  as  constitu- 
ents in  several  silicates. 

Yttrocerite. 
Massive,  of  a  violet-blue  color,  somewhat  resembling  a 


202  DESCRIPTIONS   OP   MINERALS. 

purple  fluor-  spar  ;  sometimes  reddish-brown.  Opaque. 
Lustre  glistening.  II.  =  4-5.  G.  =  3'4-3'5. 

(Composition.  Fluorine  25'1,  lime  47*6,  cerium  protox- 
ide 18*2,  and  yttria  9*1.  Infusible  alone  before  the  blow- 
pipe. 

Obs.  From  Finbo  and  Broddbo,  near  Fahlun,  in  Sweden, 
with  albite  and  topaz  in  quartz.  Also  from  Mt.  Mica, 
Maine  ;  Massachusetts,  probably  in  Worcester  County;  and 
from  Amity,  Orange  County,  N.Y. 

Fluocerite  and  Fluocerine  are  other  fluorides  containing  cerium,  from 
Sweden. 

Samarskite. 

Trimetric.  /A  7=122°  46'.  Usually  massive,  without 
cleavage,  with  a  velvet-black  color  and  shining  submetallic 
lustre.  Streak  dark-reddish  brown.  Opaque.  H.=  5*5-6. 
G.  =  5-C-5-8. 

Composition.  Analyses  of  the  American  afford  Columbia 
and  tantalic  pentoxide,  with  sesquioxides  of  yttrium  (12-15 
per  cent.),  cerium,  iron,  and  oxide  of  uranium.  In  the 
closed  tube  decrepitates  and  glows.  B.B.  fuses  on  the 
edges  to  a  black  glass.  With  salt  of  phosphorus  in  both 
flames,  an  emerald-green  bead. 

Obs.  Occurs  at  Miask,  in  the  Ural  ;  also  in  masses, 
sometimes  weighing  many  pounds,  at  the  Mica  mines  of 
Western  North  Carolina,  along  with  columbite.  • 

Noldite  is  near  samarskite,  but  contains  4 "62  of  water. 

Fergusonite.  A  hydrous  columbate  of  yttrium,  erbium,  cerium. 
Color  brownish  black  ;  lustre  dull,  but  brilliantly  vitreous  on  a  sur- 
face of  fracture.  B.B.  infusible,  but  loses  its  color.  From  Sweden, 
Cape  Farewell,  Greenland,  and  Rockport,  Mass. 

Kochelite  is  near  fergusonite. 

Yttro-tantalite.  A  tantalate  and  columbate  of  yttrium,  erbium,  and 
iron.  The  different  varieties  are  the  black,  the  yellow,  and  brown  or 
dark-colored.  They  are  infusible.  From  Ytterby,  Sweden,  and  at 
Broddbo  and  Finbo,  near  Fahlun. 

Euxenite.  A  columbate  and  tantalate  of  yttrium,  uranium,  erbium, 
and  cerium.  Massive.  Color  brownish  black.  Streak  reddish  brown, 
B.B.  infusible.  From  Norway;  also  from  N.  Carolina. 

Sipylite.  A  columbate  and  tantalate  of  erbium  and  yttrium,  re- 
sembling fergusonite  in  aspect.  From  Amherst  County,  Va. 

Pyrochlore,  Microlite,  Disanalyte,  under  CALCIUM,  p.  214. 

jEschynite.  In  crystals,  black  to  brownish  yellow  ;  lustre  resinous 
to  submetallic  ;  streak  gray  to  yellowish  brown  or  black.  H.  =5-6. 
G.  =4'9-5  1.  A  columbate  and  titanate  of  cerium,  thorium,  and  lan- 
thanum. From  Miask,  in  the  Urals,  in  feldspar  with  mica  and  zircon. 

Polymignite  and  Polycrase.     Related  to  seschynite, 


COMPOUNDS  OF   CERIUM,    YTTRIUM,    LANTHANUM.  203 

Rogersite.    A  hydrous  columbate  of  yttria,  in  whitish  crusts,  on 

samarskite.     From  N.  Carolina. 

Monazite. 

Monoclinic.  In  modified  oblique  rhombic  prisms  ;  I/\I 
=  93°  10'.  Perfect  and  brilliant  basal  cleavage.  Observed 
only  in  small  imbedded  crystals. 

Color  brown,  brownish  red  ;  subtransparent  to  nearly 
opaque.  Lustre  vitreous  inclining  to  resinous.  Brittle. 
H.  =  5.  G.  =4-8-51. 

Composition.  A  phosphate  containing  cerium,  lantha- 
num, yttrium,  didymium  and  thorium,  with  also  a  little 
tin,  mano-anese,  and  lime.  B.B.  it  colors  the  flame  green 
when  moistened  with  sulphuric  acid  and  heated.  Difficultly 
soluble  in  acids. 

Diff.  The  brilliant  easy  transverse  cleavage  distinguishes 
monazite  from  sphene. 

Obs.  Occurs  near  Slatoust,  Eussia.  In  the  United 
States  it  is  found  in  small  brown  crystals,  disseminated 
through  a  mica  slate  at  Norwich,  Conn.  ;  also  at  Chester, 
Conn.,  and  Yorktown,  Westchester  County,  N.  Y. 

Cryptolite.  A  cerium  phosphate  in  minute  prisms  (apparently  six. 
sided),  found  with  the  apatite  of  Arendal,  Norway.  Color  pale  wine- 
yellow.  G.=4'6. 

Churchite.  A  phosphate  of  cerium,  didymium  and  calcium  ;  from 
Cornwall. 

Xenotime,  An  yttrium  phosphate  having  a  yellowish-brown  color, 
pale  brown  streak,  opaque,  and  resinous  in  lustre.  Crystals  square 
prisms,  with  perfect  lateral  cleavage.  H.  =4-5.  G.  =4'G.  Infusible 
alone  before  the  blowpipe  ;  insoluble  in  acids.  From  Lindesnaes, 
Norway  ;  Ytterby,  Sweden  ;  gold  washings  of  Clarkesville,  Ga.,  and 
McDowell  County,  N.  C. 

Parisite.  Is  a  carbonate  containing  cerium,  lanthanum,  and  didy« 
rnium,  with  fluorine.  From  New  Granada. 

Lantlianite.  Occurs  in  thin  minute  tables  or  scales  of  whitish  or 
yellowish  color,  and  is  a  hydrous  lanthanum  carbonate.  From  Bast- 
nas,  Sweden,  and  Saucon  Valley  in  Lehigh  County,  Pa. 

Tengerite.  An  yttrium  carbonate.  Found  in  thin  coatings  at  Yt- 
terby, Sweden. 

Rliabdophane,  A  didymium  and  erbium  phosphate ;  from  Corn- 
wall, with  sphalerite  (blende),  which  it  resembles. 

Rutherfordite.  A  blackish-brown  vitreo-resinous  mineral.  From 
the  gold  mines  of  Rutherford  County,  N.  C. 

Allanite,  Gadolinite,  Keilhauite,  and  Tscheffkinite,  are  silicates  con- 
taining either  cerium  or  yttrium. 


204  DESCRIPTIONS   OF   MINERALS. 

MAGNESIUM. 

Magnesium  occurs,  in  nature,  as  an  oxide  or  hydrated 
oxide,  and  in  the  condition  of  sulphate,  borate,  nitrate, 
phosphate,  carbonate  and  silicate. 

The  sulphates  and  nitrate  of  magnesia  are  soluble  in 
water,  and  are  distinguished  by  their  bitter  taste  ;  the 
other  native  magnesian  salts  are  insoluble.  The  presence 
of  magnesia,  when  no  metallic  oxides  are  present,  is  indi- 
cated by  a  blowpipe  experiment,  explained  on  page  87. 

Periclasite.— Periclase.     Magnesium  Oxide. 

Isometric.  In  small  grayish  to  dark-green  imbedded 
crystals,  with  cubic  cleavage.  H.  nearly  G.  G.— 3-674. 

Composition.  Mg  0  (or  the  same  as  for  magnesia  alba  of 
the  shops),  with  a  little  iron.  B.B.  infusible.  Soluble  in 
acids  without  effervescence. 

From  Mount  Somma,  Vesuvius,  Italy. 

Brucite. — Magnesium  Hydrate. 

Ehombohedral.  In  foliated  hexagonal  prisms  and  plates; 
structure  thin  foliated,  and  thin  laminae  easily  separated 
and  translucent ;  flexible  but  not  elastic.  Also  fibrous. 
Lustre  pearly.  Color  white,  often  grayish  or  greenish. 
H.=2-5.  G.=2'35. 

Composition.  Mg02H2=:  Magnesia  69-0,  water  31-0=100. 
B.B.  infusible,  but  becomes  opaque  and  alkaline.  Soluble 
in  hydrochloric  acid  without  effervescence. 

Diff.  It  resembles  talc  and  gypsum,  but  is  soluble  in 
acids  ;  it  differs  from  heulanditc  and  stilbite  also  by  its  in- 
fusibility. 

Obs.  Occurs  in  serpentine  at  Hoboken,  N.  J.  ;  in  Rich- 
mond County,  N.  Y.  ;  in  Dutchess  County,  1ST.  Y. ,  at 
Brewster's  ;  at  Texas,  in  Pennsylvania ;  also  at  Swinaness, 
in  Unst,  one  of  the  Shetland  Isles. 

The  fibrous  variety  has  been  called  nemalite;  it  resembles 
amianthus  ;  it  occurs  at  Hoboken. 

Hydromagnesite.  A  pearly  crystalline,  or  earthy,  white,  hydrous 
carbonate  of  magnesia,  from  Hoboken,  N.  J.,  Texas,  Pa.,  and  elsewhere. 

Spinel  contains  oxygen  and  magnesium  along  with  aluminum.  See 
page  195.  Magnesium  is  also  present  in  some  magnetite,  a  variety  of 
which  is  called  magnoferrite. 


COMPOUNDS   OF   MAGNESIUM.  203 

Chlwmagnesite.  A  magnesium  chloride  from  Vesuvius. 
Carnallite.  A  hydrous  magnesium-potassium  chloride. 
Tachydrile.  A  hydrous  magnesium-calcium  chloride. 

Epsomite. — Epsom  Salt.     Magnesium  Sulphate. 

Trimetric.  /A  7=  90°  34'.  Cleavage  perfect  parallel  with 
the  shorter  diagonal.  Usually  in  fibrous  crusts,  or  botry- 
oidal  masses,  of  a  white  color.  Lustre  vitreous  to  earthy. 
Very  soluble,  and  taste  bitter  and  saline. 

Composition.  Mg  04  S  +  7aq  =  Sulphur  trioxide  32*5,  mag- 
nesia 16'3,  water  51*2  =  100.  Liquefies  in  its  water  of  crys- 
tallization when  heated.  Gives  much  water  which  has  an 
acid  reaction,  in  the  closed  glass  tube.  B.B.  on  charcoal 
fuses,  but  finally  gives  an  infusible  mass  that  turns  pink 
when  moistened  with  cobalt  nitrate  and  ignited. 

Diff.  The  fine  spicula-like  crystalline  grains  of  Epsom 
salt,  as  it  appears  in  the  shops,  distinguish  it  from  Glauber 
salt,  which  occurs  usually  in  thick  crystals. 

Obs.  The  floors  of  the  limestone  caves  of  the  West  often 
contain  Epsom  salt  in  minute  cr}rstals  mingled  with  the 
earth.  In  the  Mammoth  Cave,  Ky.,  it  adheres  to  the  roof 
in  loose  masses  like  snowballs.  It  occurs  as  an  efflores- 
cence in  the  galleries  of  mines  and  elsewhere.  The  fine 
efflorescences  suggested  the  old  name  hair-salt. 
•  At  Epsom,  in  Surrey,  England,  it  occurs  dissolved  in  min- 
eral springs,  and  from  this  place  the  salt  derived  the  name 
it  bears.  It  occurs  at  Sedlitz,  Aragon,  and  other  places  in 
Europe  ;  also  in  the  Cordilleras  of  Chili  ;  and  in  a  grotto  in 
Southern  Africa,  where  it  forms  a  layer  an  inch  and  a  half 
thick. 

Its  medical  uses  are  well  known.  It  is  obtained  for  the 
arts  from  the  bittern  of  sea-salt  works,  and  quite  largely 
from  magnesian  calcium  carbonate,  by  decomposing  it  with 
sulphuric  acid.  The  sulphuric  acid  takes  the  lime  and 
magnesia,  expelling  the  carbonic  acid  ;  and  the  sulphate  of 
magnesium  remaining  in  solution  is  poured  off  from  the  cal- 
cium sulphate,  which  is  insoluble.  It  is  then  crystallized  by 
evaporation. 

Polylialite.  A  brick-red  saline  mineral,  with  a  weak  bitter  taste, 
occurring  in  masses  which  have  a  somewhat  fihrous  appearance.  A 
hydrous  calcium- magnesium  sulphate. 

Kieserite.     A  hydrous  magnesium  sulphate  ;  from  Stassfurt. 

Picromeride.  A  hydrous  potassium  -  magnesium  sulphate ;  from 
Stassfurt. 


206 


DESCRIPTIONS   OF   MINERALS. 


Bladite.  A  hydrous  sodium -magnesium  sulphate  ;  from  the  salt 
mines  of  Ischl,  and  near  Mendoza. 

Jjoewcite.  A  hydrous  sodium  magesium  sulphate  ;  from  Ischl.  Con' 
tains  more  sulphur  trioxide  than  Bleed ite. 


Isometric. 
1. 


traces. 


Boracite. — Magnesium  Borate. 

Cleavage  octahedral ;  but  only 
Usual  in  cubes  with  only  the 
alternate  angles  replaced  ;  or 
having  all  replaced,  but  four 
of  them  different  from  the 
other  four.  The  crystals  are 
translucent  and  "seldom  more 
than  a  quarter  of  «n  inch 
through.  Also  massive.  Color  white  or  grayish  ;  sometimes 
yellowish  or  greenish.  Lustre  vitreous.  H.  —  7  when  in 
crystals,  but  softer  when  massive.  G.  =2-97.  Becomes 
electric  when  heated,  the  opposite  angles  of  the  cube  be- 
coming of  opposite  poles. 

Composition.  Mg3  015  B8  +  JMg  C12=  Boron  trioxide  62-0, 
magnesia  31'0,  chlorine  7*0=100.  B.B.  fuses  easily  with  in- 
tumescence coloring  the  flame  green.  The  fused  globule 
becomes  crystalline  on  cooling.  Dissolves  in  hydrochloric 
acid,  and  moistened  with  cobalt  nitrate  turns  pink  on  igni- 
,tion. 

Diff.  Distinguished  readily  by  its  form,  high  hardness, 
And  pyro  electric  properties. 

Obs.  Boracite  is  found  only  with  gypsum  and  common 
salt.  It  occurs  near  Luneberg  in  Lower  Saxony,  and  near 
Kiel  in  the  adjoining  duchy  of  Holstein,  also  at  Stassfurth, 
Prussia. 

Rhodizite.  Resembles  horacite  in  its  crystals,  hut  tinges  the  blow- 
pipe flame  deep  red.  It  is  supposed  to  be  a  lime-boracite.  Occurs 
with  the  red  tourmaline  of  Siberia.  Ludwigite.  A  magnesium-iron 
borate  ;  fibrous  and  dark  green  to  black. 

Szuibelyite.  A  hydrous  magnesium  borate,  from  Southeastern 
Hungary 

Warwickite.  In  rhombic  prisms  of  93°  to  94°,  hair-brown  to  black 
with  sometimes  a  copper-red  tinge.  A  magnesium  titanium  borate  ; 
from  granular  limestone  of  Edenville,  N.  Y. 

Sussexite.  A  hydrous  magnesium-manganese  borate.  Fibrous  and 
pearly.  G=3  42.  from  Mine  Hill.  Franklin  Furnace,  Sussex  Co.,  N.  J. 

Nttromagnesite.  Occurs  in  white  deliquescent  efflorescences,  having 
a  bitter  taste,  associated  with  calcium  nitrate,  in  limestone  caverns.  It 
is  used,  like  its  associate,  in  the  manufacture  of  saltpetre. 

Wugnerite.   A  magnesium  fluo-phosphate,  occurring  in  yellowish  or 


COMPOUNDS    OF    CALCIUM.  20? 

frayish  oblique  rhombic  prisms.      Insoluble.      H.  =5-5 '5.     G.^3'1 
rom  Salzburg,  Austria.     Kjeralfine  is  near  wagnerite. 
Hcernisite  and  ficessleritc  are  hydrous  calcium  arsenates. 
Luneburgite.     A  magnesium  boro-phosphate,  from  Liineburg. 

Magnesite.— Magnesium  Carbonate. 

Rhombohcdral.  R  :  72=107°  29'.  Cleavage  rhomboliedral, 
perfect.  Often  massive,  either  granular,  or  compact  and 
porcelain-like,  in  tuberose  forms  ;  also  fibrous. 

Color  white,  yellowish  or  grayish-white,  or  brown.  Lus- 
tre vitreous ;  fibrous  varieties  often  silky.  Transparent  to 
opaque.  H.- 3— 4'5.  G.  =  3. 

Composition.  Mg05C  =  Carbon  dioxide  52*4,  magnesia 
47-6^100.  Infusible  before  the  blowpipe.  After  ignition 
has  an  alkaline  reaction.  Nearly  insoluble  in  cold  dilute 
hydrochloric  acid,  but  dissolves  with  effervescence  in  hot. 

Diff.  Kesembles  some  varieties  of  calcite  and  dolomite  ; 
but  'from  a  concentrated  solution  no  calcium  sulphate  is 
precipitated  on  adding  sulphuric  acid.  The  fibrous  variety 
is  distinguished  from  other  fibrous  minerals  by  its  efferves- 
c.ence  in  hot  acid,  which  shows  it  to  be  a  carbonate. 

Obs.  Magnesite *is  usually  associated  with  magnesian 
rocks,  especially  serpentine.  At  Hoboken,  N.  J.,  it  occurs 
in  this  rock  in  fibrous  seams  ;  similarly  at  Lynnfield,  Mass.; 
and  in  Canada,  at  Bolton,  imperfectly  fibrous,  traversing 
white  limestone. 

When  abundant  it  is  a  convenient  material  for  the  manu- 
facture of  magnesium  sulphate  or  Epsom  salt,  to  make 
which,  requires  simply  treatment  with  sulphuric  acid. 

Ilydromagncsite.     A  hydrous  magnesium  carbonate.     Occurs  with 
serpentine,  at  Hoboken,  but  more  abundantly  in  Lancaster  Co. ,  Penn. 
Dolomite.  A  magnesium  and  calcium  carbonate.     See  page  219. 

CALCIUM. 

Calcium  exists  in  nature  in  the  state  of  fluorite,  and  this 
is  its  only  binary  compound.  It  occurs  in  ternaries  in  the 
state  of  sulphate,  borate,  columbate,  phosphate,  arsenate, 
carbonate,  titanate  and  silicate.  The  carbonate  (calcite  and 
limestone)  is  one  of  the  three  most  abundant  of  minerals. 
The  fluoride  and  sulphate,  and  some  silicates,  are  also  of 
very  common  occurrence. 


208 


DESCRIPTIONS   OP   MINERALS. 


With  the  exception  of  the  calcium  nitrate,  none  of  the 
native  salts  of  lime  are  soluble  in  water  except  in  small 
proportions.  They  give  no  odor,  and  no  metallic  reaction 
before  the  blowpipe ;  but  they  tinge  the  flame  red,  and 
many  of  them  give  up  a  part  of  their  acid  constituent,  and 
become  caustic  and  react  alkaline.  The  specific  gravity  is 
below  3  '2,  and  hardness  not  above  5. 

Fluorite. — Fluor  Spar.     Calcium  Fluoride. 

Isometric.  Cleavage  octahedral,  perfect.  Commonly  in 
crystals  ;  rarely  fibrous  ;  often  compact,  coarse  or  fine  gran- 
ular. Figures  1  to  4  repffesent  common  forms. 


3. 


Colors  usually  bright ;  white,  or  some  shade  of  light 
green,  purple,  or  clear  yellow  are  most  common  ;  rarely 
rose-red  and  sky-blue  ;  colors  of  massive  varieties  often 
banded.  Transparent,  translucent  or  subtranslucent.  H  =  4. 
G.  =3-3 '26.  Brittle. 

Composition.  CaF2=Fluorine  48*7,  calcium  51 '3  — 100. 
Phosphoresces  when  gently  heated  in  the  dark,  affording 
light  of  different  colors  ;  in  some  varieties  emerald-green  ; 
in  others,  purple,  blue,  rose-red,  pink,  or  orange.  B.B. 
decrepitates,  and  ultimately  fuses  to  an  enamel,  which  pos- 
sesses an  alkaline  reaction  ;  pulverized  and  moistened  with 
sulphuric  acid,  hydrofluoric  acid  gas  is  given  off  which  cor- 
rodes glass.  The  name  Clilorophane  has  been  given  to  the 
variety  that  affords  a  bright  green  phophorescence. 

Diff.  In  its  bright  colors,  fluorite  resembles  some  of  the 
gems,  but  its  softness  and  its  easy  octahedral  cleavage  when 
crystallized  at  once  distinguish  it.  Its  strong  phosphores- 
cence is  a  striking  characteristic;  and  also  its  affording 


COMPOUNDS   OF   CALCIUM.  209 

easily,  with  sulphuric  acid  and  heat,  a  gas  that  corrodes 
glass. 

Obs.  Fluorite  occurs  in  gneiss,  mica  schist,  clay  slate, 
limestone,  and  sparingly  in  beds  of  coal  either  in  veins 
or  occupying  cavities,  or  as  imbedded  masses.  It  is  the 
gangue  in  some  lead  mines. 

Cubic  crystals  of  a  greenish  color,  over  a  foot  each  way, 
have  been  obtained  at  Muscolonge  Lake,  St.  Lawrence 
County,  N.  Y. ;  near  Shawneetown  on  the  Ohio,  a  beautiful 
purple  fluor  in  grouped  cubes  of  large  size  is  obtained  from 
limestone  and  the  soil  of  the  region  ;  at  Westmoreland,  N". 
H.,  at  the  Notch  in  the  White  Mountains,  Blue  Hill  Bay, 
Maine,  Putney,  Vt.,  and  Lockport,  N.  Y.,  are  other  locali- 
ties. The  chlorophane  variety  is  found  with  topaz  at  Trum- 
bull,  Conn. 

In  Derbyshire,  England,  fluor  spar  is  abundant,  and  hence 
it  has  received  the  name  of  Derbyshire  spar.  It  is  a  com- 
mon mineral  in  the  mining  districts  of  Saxony. 

Calcium  fluoride  also  exists  in  the  enamel  of  teeth,  in 
bones  and  some  other  parts  of  animals  ;  also  in  certain  parts 
of  many  plants  ;  and  by  vegetable  or  animal  decomposition 
it  is  afforded  to  the  soil,  to  rocks,  and  also  to  coal  beds  in. 
which  it  has  been  detected. 

Massive  fluor  receives  a  high  polish,  and  is  worked  into 
vases,  candlesticks  and  various  ornaments,  in  Derbyshire, 
England.  Some  of  the  varieties  from  this  locality,  consist- 
ing of  rich  purple  shades  banded  with  yellowish  white,  are 
very  beautiful.  The  mineral  is  difficult  to  work  because 
brittle.  Fluor  spar  is  also  used  for  obtaining  hydrofluoric 
acid,  which  is  employed  in  etching.  To  etch  glass,  a  pic- 
ture, or  whateverdesign  it  is  desired  to  etch,  is  traced  in 
the  thin  coating  of  wax  with  which  the  glass  is  first  covered; 
a  very  small  quantity  of  the  liquid  hydrofluoric  acid  is  then 
washed  over  it ;  on  removing  the  wax,  in  a  few  minutes,  the 
picture  is  found  to  be  engraved  on  the  glass.  The  same 
process  is  used  for  etching  seals,  and  any  siliceous  stone 
will  be  attacked  with  equal  facility.  This  application  of 
fluor  spar  depends  upon  the  strong  affinity  between  fluorine 
and  silicon.  Fluor  spar  is  also  used  as  a  flux  to  aid  in  re- 
ducing copper  and  other  ores,  and  hence  the 


£10  DESCRIPTIONS   OF   MINERALS. 

Gypsum.— Hydrous  Calcium  Sulphate. 

Monoclinic.  /A 7=143°  42' ;  22A2i  +  lH°  42'.  Figure 
2  represents  a  common  twin  (or  arrow-head)  crystal.  Cleav- 
age parallel  to  i-l  very  easy,  affording 
thin  pearly  laminae ;  parallel  to  0,  im- 
perfect, giving  a  vitreous  surface ;  par- 
allel to  /,  fibrous.  Occurs  also  in  lam- 
inated masses,  often  of  large  size  ;  in 
fibrous  masses,  with  a  satin  lustre ;  in 
stellated  or  radiating  forms  consisting  of 
narrow  laminae  ;  also  granular  and  com- 
pact. 

When  pure  and  crystallized  it  is  as  clear  and  pellucid  as 
glass,  and  has  a  pearly  lustre.  Other  varieties  are  gray,  yel- 
low, reddish,  brownish,  and  even  black,  and  opaque.  1-1.= 
1  '5-2,orso  soft  as  to  be  scratched  by  the  finger-nail.  G.  =  2'33, 
The  plates  bend  in  one  direction  and  are  brittle  in  another. 
Composition.  Ca  04S  +  2  aq— Sulphur  trioxide  4(ro,  lime 
32-6,  water  20 '9  =  100.  B.B.  becomes  instantly  white  and 
opaque  and  exfoliates,  and  then  fuses  to  a  globule,  which 
when  placed  upon  moistened  turmeric  paper  shows  an  alka- 
line reaction.  In  a  closed  tube  much  water  is  given  off. 
Dissolves  quietly  in  hydrochloric  acid,  and  the  solution  gives 
a  heavy  precipitate  with  barium  chloride. 
The  principal  varieties  are  as  follows  : 
Selenite,  including  the  transparent  crystallized  gypsum, 
so  called  in  allusion  to  its  color  and  lustre  from  selene,  the 
Greek  word  for  moon. 

Radiated  and  Plumose  gypsum,  having  a  radiated  struc- 
ture. 

Fibrous  gypsum  or  satin  S2)ar,  white  and  delicately  fibrous. 
Snowy  g ijp sum  and  Alabaster,  including  the  white  or  light- 
colored  compact  gypsum  having  a  very  fine  grain. 

Diff.  The  foliated  gypsum  resembles  some  varieties  of 
heulandite,  stilbite,  talc,  and  mica  ;  and  the  fibrous  looks 
like  fibrous  carbonate  of  lime,  asbestus  and  some  of  the 
fibrous  zeolites  ;  but  gypsum  in  all  its  varieties  is  readily 
distinguished  by  its  softness  ;  its  becoming  an  opaque  white 
powder  immediately  and  without  fusion  before  the  blow- 
pipe, and  by  not  effervescing  or  gelatinizing  with  acids. 

Obs.  Gypsum  forms  extensive  beds  in  certain  limestones 
and  clay  beds,  and  also  occurs  in  volcanic  regions.  New 
York,  near  Lockport,  affords  beautiful  selenite  and  snowy 


-     COMPOUNDS   OP   CALCIUM.  211 

gypsum  in  limestone.  At  Camillas  and  Manlius,  N.  Y.,  and 
in  Davidson  County,  Term.,  are  other  localities.  Fine  crys- 
tals of  the  form  represented  in  figure  5  come  from  Poland 
and  Canfield,  Ohio,  and  large  groups  of  crystals  from  St. 
Mary's  in  Maryland.  Troy,  N.  Y.,  also  affords  crystals  in 
clay.  In  Mammoth  Cave,  Kentucky,  alabaster  occurs  in 
imitation  of  flowers,  leaves,  shrubbery,  and  vines.  Alabas- 
ter is  obtained  at  Castelino  in  Italy,  35  miles  from  Leghorn. 
Massive  gypsum  occurs  abundantly  in  New  York,  from 
Syracuse  westward  to  the  western  extremity  of  Genesee 
County,  accompanying  the  rocks  which  afford  the  brine 
springs ;  also  in  New  Brunswick,  especially  at  Hillsboro', 
where  part  is  excellent  alabaster;  in  Hants,  Colchester,  and 
other  districts  in  Nova  Scotia;  also  in  Ohio,  Illinois,  Vir- 
ginia, Tennessee,  Arkansas, and  Nova  Scotia;  and  in  con- 
nection with  the  Triassic  beds  of  the  Rocky  Mountain 
region;  also  abundant  in  Nevada  and  California.  It  is 
abundant  also  in  Europe. 

Gypsum,  when  calcined,  loses  its  water,  becomes  white, 
is  easily  ground  to  a  powder.  This  powder,  when  mixed 
with  a  little  water,  takes  up  water  again  and  becomes  hard 
and  compact.  This  gypsum  is  plaster  of  Paris,  and  is  used 
for  taking  casts,  making  models,  and  forgiving  a  hard  finish 
to  walls.  Alabaster  is  cut  into  vases  and  various  ornaments, 
statues,  etc.  It  owes  its  beauty  for  this  purpose  to  its  snowy 
whiteness,  translucency,  and  fine  texture.  Moreover,  owing 
to  its  softness,  it  can  be  cut  or  carved  with  common  cutting 
instruments.  Gypsum  is  ground  up  and  used  for  improving 
soils. 

Anhydrite. — Anhydrous  Calcium  Sulphate. 

Trimetric.  In  rectangular  and  rhombic  prisms,  cleaving 
easily  in  three  directions,  and  readily  breaking  into  square 
blocks.  /A/=100°30"*;  1UH=85°  and 
95°.  Occurs  also  fibrous  and  lamellar,  often 
contorted  ;  also  coarse  and  fine  granular, 
and  compact. 

Color  white,  or  tinged  with  gray,  red,  or 
blue.  Lustre  more  or  less  pearly.  Trans- 
parent to  subtranslucent.  II.  — 3-3*5.  G. 
=  2'<J-3. 

Composition.  Ca  04S  =  Sulphur  trioxide 
58 '8,  lime  41-2  =  100.  It  is  an  anhydrous 
calcium  sulphate.  B.B.  and  with  acids, 


DESCRIPTIONS   OF   MINERALS. 

its  reactions  are  like  those  of  gypsum,  except  that  in  the 
closed  tube  it  gives  no  water. 

A  scaly  massive  variety  containing  a  little  silica  has  been 
named  Vulpinite;  contorted  concretionary  kinds  are  some- 
times called  Tripestone.  Anhydrite  is  called  by  miners  hard" 
plaster,  because  harder  than  gypsum. 

I) iff.  Its  square  forms  of  crystallization  and  cleavage  are 
good  distinguishing  characters.  Its  three  easy  cleavages,  at 
right  angles  with  one  another,  look  as  if  the  crystalliza- 
tion were  cubic ;  but  there  is  some  difference  in  the  ease 
with  which  they  may  be  obtained. 

Obs.  A  fine  blue  crystallized  anhydrite  occurs  with  gyp- 
sum and  calcareous  spar  in  a  black  limestone  at  Lockport, 
and  near  Windsor  in  Nova  Scotia,  and  Hillsboro'  in  New 
Brunswick.  Foreign  localities  are  at  the  salt  mines  of  Bex 
in  Switzerland,  Hall  in  the  Tyrol,  Ischl  in  Upper  Austria, 
Wieliczka  in  Poland,  and  elsewhere. 

The  vulpinite  variety  is  sometimes  cut  and  polished  for 
ornamental  purposes. 

Becliilite.  A  hydrous  calcium  borate  occurring  as  an  incrustation  at 
the  Tuscan  lagoons,  Italy.  A  "  hydrous  borate  of  lime  "  reported  by 
Hayes  from  Iquique,  Peru,  has  been  called  Hayesine ;  but  its  com- 
position has  been  questioned,  it  being  referred  to  Ulexite.  Howlite, 
A  hydrous  calcium  borate,  containing  silica  ;  Windsor,  Nova  Scotia. 
Called  also  Silicoborocalcite. 

Ulexite  or  Boronatrocalcite.  A  hydrous  calcium-sodium  borate,  in 
aggregations  of  fibres,  from  the  dry  plains  of  Iquique,  Southern  Peru; 
Nova  Scotia,  at  Windsor,  Brookville,  and  Newport ;  and  Nevada,  in 
Columbus  mining  district,  and  at  Thiel  Salt  Marsh,  in  Esmeralda 
County. 

OryptomorpMte.  Another  hydrous  calcium-sodium  borate  ;  Windsor, 
Nova  Scotia.  Priceite  is  a  calcium  borate  of  white  color  and  chalky 
aspect,  from  Curry  County,  Oregon. 

Hydrdboracite.  A  hydrous  calcium-magnesium  borate,  resembling 
gypsum  in  aspect. 

Scheelite.  Calcium  tungstate,  of  pale  yellowish-white  color;  H.= 
4'5-5.  G.=r5'9-6'l.  From  Monroe,  Conn.;  North  Carolina  ;  Mammoth 
mining  district,  Nevada ;  Charity  Mine,  Idaho  ;  Golden  Queen  Mine, 
Lake  Co.,  Colorado;  Seattle,  Washington  Territory;  at  Caldbeck 
Fell,  near  Keswick,  England  ;  in  Bohemia,  Hartz,  Saxony,  Hungary, 
Sweden,  Vosges.  Cuproscheelite  has  part  of  the  calcium  replaced  by 
copper ;  from  La  Paz,  Lower  California. 

Apatite. — Calcium  Phosphate. 

Hexagonal.  In  hexagonal  prisms.  The  annexed  figure 
represents  a  common  form.  Cleavage  imperfect.  Usually 
occurs  in  crystals  ;  but  occasionally  massive ;  sometimes 


COMPOUNDS    OP   CALCIUM.  213 

mammillary  with  a  compact  fibrous  structure. 
Small  crystals  are  occasionally  transparent 
and  colorless,  but  the  usual  color  is  green, 
often  yellowish  green,  bluish  green,  and  gray- 
ish green  ;  sometimes  yellow,  blue,  reddish 
or  brownish.  Coarse  crystals  nearly  opaque. 

Lustre  vitreous  to  subresinous.  H.=5.  G. 
=  3-3-25.  Brittle.  Some  varieties  phospho- 
resce when  heated,  and  some  become  electric 
by  friction. 

Composition.  Ca?  08  P2-J-  J  (C12,  F2)  =  if  without  fluorine 
Phosphorus  pentoxide  40'92,  lime  53 '80,  chlorine  6 '82=100. 
When  chlorine  is  present  in  place  of  fluorine  it  is  called 
cMor-apatite,  and  when  the  reverse,  fluor-apatite.  B.B.  in- 
fusible except  on  the  edges.  Dissolves  slowly  in  nitric  acid 
without  effervescence.  Its  constituents  are  contained  in 
the  bones  and  ligaments  of  animals,  and  the  mineral  has 
probably  been  derived  in  many  cases  from  animal  fossils.* 

Massive  apatite  is  often  called  Phosphorite;  and  the  pale 
yellowish-green  crystals,  Asparagus  stone.  Osteolite  is  a 
white  earthy  apatite.  Eupyrchroite  is  a  fibrous  mammil- 
lary variety  from  Crown  Point,  Essex  County,  N.  Y. 

fossil  excrements,  called  coprolites,  occur  in  stratified 
rocks,  and  sometimes  constitute  extended  beds  ;  and  they 
consist  chiefly  of  calcium  phosphate.  Guano  contains  more 
or  less  calcium  phosphate  along  with  hydrous  phosphates 
and  some  impurities. 

Diff.  Distinguished  from  beryl  by  its  inferior  hardness, 
it  being  easily  scratched  with  a  knife  ;  from  calcite  by  dis- 
solving in  acids  without  effervescence  ;  from  pyromorphite 
by  its  difficult  fusibility,  and  giving  no  metallic  reaction 
before  the  blowpipe.  Phosphoric  acid  may  be  detected  by 
moistening  it  with  sulphuric  acid  and  igniting  it  B.B., 
when  it  imparts  a  dirty  green  color  to  the  flame. 

Obs.  Apatite  occurs  in  gneiss,  mica  schist,  hornblende 
schist,  granular  limestone.  In  microscopic  crystals  it  is 
sparingly  present  in  almost  all  crystalline  rocks,  the  ig- 
neous as  well  as  metainorphic.  The  best  crystals  in  the 
United  States  occur  in  granular  limestone  ;  the  crystals 
from  the  limestone  of  St.  Lawrence  County,  N.  Y.,  are 

*  Bones  contain  25  per  cent,  of  calcium  phosphate,  with  some  fluoride  of  calcium,  3 
to  12  per  cent,  of  calcium  carbonate,  some  magnesium  phosphate  and  sodium  chloride, 
besides  33  per  cent,  of  animal  matter. 


214  DESCRIPTIONS   OF  MINERALS. 

among  the  largest  yet  discovered  in  any  part  of  the  world; 
one  from  Kobinson's  farm  measured  a  foot  in  length  and 
weighed  18  pounds;  but  they  are  nearly  opaque  and  the 
edges  are  usually  rounded.  They  occur  with  scapolite, 
sphene,  etc.  Edenville  and  Amity,  Orange  County,  N.  Y., 
afford  fine  crystals  from  half  an  inch  to  twelve  inches 
long.  At  Westmoreland,  N.  H.,  fine  crystals  are  obtained 
in  a  vein  of  feldspar  and  quartz  ;  also  at  Blue  Hill  Bay 
in  Maine.  Bolton,  Chesterfield,  Chester,  Mass.,  are  other 
localities.  A  beautiful  blue  variety  is  obtained  at  Dixon's 
quarry,  Wilmington,  Delaware.  Abundant  in  Burgess, 
Elmsley,  Grand  Calumet  Id.,  Hull,  Buckingham,  Port- 
land, etc.,  in  Canada. 

The  name  apatite,  from  the  Greek  apatao,  to  deceive,  was 
given  in  allusion  to  the  mistake  of  early  mineralogists  re- 
specting the  nature  of  some  of  its  varieties. 

Apatite,  when  abundant,  is  used  like  guano  as  a  fertilizer, 
on  account  of  its  phosphoric  acid.  To  make  it  capable  of 
being  taken  up  by  plants  it  is  treated  first  with  a  small  por- 
tion of  sulphuric  acid,  which  renders  the  phosphoric  acid 
soluble.  When  guano  has  been  accumulated  by  birds,  or 
other  animals,  over  coral  rock,  a  calcium  carbonate  (as  on 
some  coral  islands),  the  waters  in  filtrating  through  it  have 
often  carried  down  the  soluble  phosphoric  acid  or  phosphates 
into  the  underlying  beds  and  turned  them  into  calcium 
phosphate. 

Brushite  and  Metdbrushite.  Hydrous  calcium  phosphates,  found  in 
guano. 

PyrophospJiorite.  A  white  earthy  phosphate  from  a  guano  deposit, 
in  the  West  Indies.  Analysis  gave  it  the  composition  of  a  pyrophos- 
phate. 

Pharmacolite  and  Raiding erite  are  hydrous  calcium  arsenates. 

Nitrocalcite.     Hydrous  calcium  nitrate.     From  caverns. 

Pyrochlore.  Occurs  in  small  brown  and  brownish-yellow  isometric 
octahedrons.  A  calcium-cerium  columbate.  G.=  4 '3-4 '5.  From  Nor- 
way, Siberia. 

Microlite.  In  crystals  similar  in  form  to  those  of  pyrochlore,  but 
in  composition  a  calcium  tantalate.  G.=5'5-6.  From  Chesterfield, 
Mass. ,  and  Redding,  Conn.  Hatchettolite  is  a  lime-uranium  colum- 
bate, from  North  Carolina. 

Disanalyte.  In  cubes  in  granular  limestone,  a  columbate  and  titan- 
ate  of  calcium,  cerium  and  iron.  From  the  Kaiserstuhl. 

Romeite  and  Atopite  are  calcium  antimonates,  the  latter  containing 
also  iron  and  soda. 


COMPOUNDS   OF   CALCIUM. 


215 


Calcite. — Calc  Spar.     Calcium  Carbonate. 

Rhombohedral.    R/\R  (fig.  1)  =  105°5'.     Cleavage  easy, 
parallel  with  the  faces  of  the  fundamental  rhombohedron. 


1. 


Calcite  with  the  form  in  fig.  7  is  often  called  dog-tooth 
spar.  Occurs  fibrous  with  a  silky  lustre  ;  sometimes  lamel- 
lar ;  often  coarse  or  fine  granular,  and  compact. 

The  purest  crystals  are  transparent  with  a  vitreous  lustre  ; 
the  impure  massive  varieties  are  often  opaque,  and  without 
lustre,  and  even  earthy.  The  colors  of  the  crystals  are 
either  white  or  some  light  grayish,  reddish  or  yellowish 
tint,  rarely  deep  red  ;  occasionally  topaz-yellow,  rose  or 
violet.  The  massive  varieties  are  of  various  shades  from 
white  to  black,  generally  dull  unless  polished.  H.=3. 
G.=2-5-2-8. 

Composition.  Ca03C  =  Carbon  dioxide  44,  lime  56  =  100. 
Sometimes  impure  from  mixture  with  iron,  silica,  clay, 
bitumen,  and  other  substances.  B.B.  infusible;  colors  the 
flame  reddish,  gives  up  its  carbon  dioxide,  is  thereby  made 
caustic,  in  which  state  it  gives  an  alkaline  reaction.  Effer- 
vesces in  dilute  cold  hydrochloric  acid.  Many  varieties 
phosphoresce  when  heated. 

The  following  are  the  principal  varieties. 

Iceland  spar.  Transparent  crystalline  calcite.  first 
brought  from  Iceland.  Shows  well  double  refraction. 

Satin  spar.  A  finely  fibrous  variety  with  a  satin  lustre. 
Receives  a  handsome  polish.  Occurs  usually  in  veins  tra- 
versing rocks  of  different  kinds. 

Chalk.     White  and  earthy,  without  lustre,  and  so  soft  as 


216  DESCRIPTIONS   OP   MINERALS. 

to  leave  a  trace  on  a  board.  Forms  mountain  beds.  Most 
chalk  was  made  chiefly  out  of  the  shells  of  Rhizopods. 

Rock  milk.  AVhite  and  earthy  like  chalk,  but  still  softer, 
and  very  fragile.  It  is  deposited  from  waters  containing 
lime  in  solution.  Rock  meal  is  a  powdery  variety. 

Calcareous  tufa.  Formed  by  deposition  from  waters  like 
rock  milk,  but  more  cellular  or  porous  and  not  so  soft. 

Stalactite,  Stalagmite.  The  name  stalactite  is  explained 
on  page  60.  The  deposits  of  the  same  origin  that  cover 
the  floors  of  caverns  are  called  stalagmite.  They  generally 
consist  of  differently  colored  layers,  and  appear  banded  or 
striped  when  broken.  The  so-called  "Gibraltar  rock"  is 
stalagmite  from  n  cavern  in  the  rock  of  Gibraltar. 

Limestone  is  a  general  name  for  all  the  massive  varieties 
occurring  in  extensive  beds. 

Oolite,  Pisolite.  Oolite  is  a  compact  limestone,  consist- 
ing of  small  round  concretionary  grains,  looking  like  the 
spawn  of  a  fish  ;  the  name  is  derived  from  the  Greek  don, 
an  egg.  Pisolite,  a  name  derived  from  pisum,  the  Latin  for 
pea,  differs  from  oolite  in  being  coarser  ;  the  spherules 
often  have  a  concentric  structure,  and  thus  show  their  con- 
cretionary origin. 

Argentine.  A  white  shining  limestone  consisting  of  la- 
minae a  little  waving,  and  containing  some  silica. 

Fontainebleau  limestone.  This  name  is  applied  to  crys- 
tals of  the  form  shown  in  figure  3,  containing  a  large  pro- 
portion of  sand,  and  occurring  in  groups.  They  were  for- 
merly obtained  at  Fontainebleau,  France,  but  the  locality 
is  exhausted. 

Granular  limestone.  A  limestone  consisting  of  crystal- 
line grains,  and  hence  often  called  crystalline  limestone. 
The  coarser  varieties  when  polished  constitute  the  common 
white  and  clouded  marbles,  and  are  the  material  of  which 
"  marble "  buildings  are  made.  The  finer  are  used  for 
statuary,  and  are  called  statuary  marble.  The  best  is  as 
clear  and  fine-grained  as  loaf  sugar,  which  it  much  re- 
sembles. 

Compact  limestone.  The  limestones  breaking  with  a 
smooth  surface,  without  a  distinctly  granular  texture,  and 
dull  in  lustre  unless  polished.  The  rock  is  very  variously 
colored.  The  colors  are  sometimes  arranged  in  blotches,  or 
veins.  Kinds  that  are  handsome  when  polished  are  used 
as  marbles.  A  black  color  is  common,  and  is  usually  due  to 


COMPOUNDS    OF    CALCIUM.  21? 

carbonaceous  material  of  organic  origin,  and  is  proved  by 
the  limestones  becoming  white  when  burnt. 

Stinkstone,  Antliraconife.  A  limestone  which  gives  out 
a  fetid  odor  when  struck.  This  odor  is  caused  by  certain 
bituminous  materials  present  in  the  rock. 

Lithographic  stone.  A  very  compact  fine-grained  lime- 
stone of  a  gray  or  grayish-yellow  color. 

Hydraulic  limestone.  An  impure  limestone.  It  contains 
silica  and  alumina  in  such  a  condition  that,  when  burned,  it 
will  make  a  cement  that  hardens  under  water. 

Diff.  Distinguished  by  being  scratched  easily  with  a  knife, 
in  connection  with  strongly  effervescing  in  dilute  acid, 
and  its  complete  infusibility.  Calcite  is  not  so  hard  as 
aragonite,  and  possesses  a  very  distinct  cleavage,  which 
aragonite  does  not. 

06s.  Crystallized  calc  spar  occurs  in  magnificent  forms 
in  the  vicinity  of  Rossie,  New  York.  One  crystal  from 
there,  now  in  the  Peabody  Museum  at  New  Haven,  weighs 
165  pounds.  Some  rose  and  purple  varieties  from  this 
region  are  very  beautiful.  Large  geodes  of  the  dog-tooth 
spar  variety  occur  in  limestone  at  Lockport,  along  with 
gypsum  and  pearl  spar.  Leyden  and  Lowville,  N.  Y.,  are 
other  localities.  Bergen  Hill,  N.  J.,  affords  beautiful 
wine-yellow  crystals  in  amygdaloidal  cavities  ;  also  the 
Lake  Superior  copper  mines.  Argentine  occurs  near 
Williamsburg  and  Southampton,  Mass.  Rock  milk  covers 
the  sides  of  a  cave  at  Watertown,  JS".  Y.,  and  is  now 
forming  Stalactites  of  great  beauty  occur  in  Weir's  and 
other  caves  in  Virginia  and  in  the  Western  States  ;  also  in 
Ball's  Cave  at  Scoharie,  N.  Y.  Chalk  occurs  in  England 
and  Europe,  and  in  Western  Kansas  in  the  United  States. 
Granular  limestones  are  common  in  the  Eastern  and  At- 
lantic States,  and  compact  limestones  in  the  Middle  and 
Western  States,  and  some  beds  of  the  former  afford  excellent 
marble  for  building  and  some  of  good  quality  for  stat- 
uary. 

Any  of  the  varieties  of  this  mineral  when  burnt  form 
quicklime,  heat  driving  off  the  carbonic  acid  and  leaving 
the  lime  in  a  caustic  state.  In  this  state  it  is  used  for  mak- 
ing mortar  by  mixing  with  water  and  sand  ;  a  calcium 
hydrate  results  which  becomes  slowly  carbonated  through 
carbonic  acid  in  the  atmosphere.  See  further  the  chapter 
on  Bocks,  for  the  uses  of  limestone. 


218 


DESCRIPTIONS    OF   MINERALS. 


Aragonite. 

Trimetric.  In  rhombic  prisms;*/ A  7=116°  10'.  Cleavage 
parallel  with  /.  Usually  in  compound  crystals  having  the 
form  of  a  hexagonal  prism,  with  uneven  or  striated  sides  ; 
or  in  stellated  forms  consisting  of  two  or  three  flat  crystals 
crossing  one  another.  Transverse  sections  of  some  of  the 
compound  crystals  are  shown  in  figs.  1  to  4. 


1. 


3. 


Occurs  also  in  globular  and  coralloidal  shapes ;  also  in 
fibrous  seams  in  different  rocks. 

Color  white  or  with  light  tinges  of  gray,  yellow,  green  and 
violet.  Lustre  vitreous.  Transparent  to  translucent.  H.= 
3-5-4.  G.  =  2'931. 

Composition.  Same  as  for  calcite,  and  its  action  before 
the  blowpipe  and  with  acids  is  the  same,  except  that  it  falls 
to  powder  readily  when  heated.  Some  varieties  contain  a 
few  per  cent,  of  strontium  carbonate,  but  this  is  not  an 
essential  ingredient.  Distinguished  from  calcite  by  the 
absence  of  the  cleavage  of  the  latter,  as  well  as  the  crystal- 
line form  ;  also  by  its  higher  specific  gravity. 

Obs.  Aragonite  occurs  mostly  in  gypsum  beds  and  in 
connection  with  iron  ores ;  also  in  basalt  and  other  rocks. 
The  coralloidal  forms  are  found  in  iron  ore  beds,  and  are 
called  Flos  f err i,  flowers  of  iron.  They  look  like  a  loosely 
intertwined  or  tangled  white  cord. 

The  fios-ferri  variety  occurs  at  Lockport  with  gypsum  ; 
also  at  Edenville,  at  the  Parish  iron  ore  bed  in  Rossie,  and 
in  Chester  County,  Pennsylvania.  Aragon  in  Spain  affords 
six-sided  prisms  of  aragonite,  associated  with  gypsum.  This 
locality  gave  the  name  to  the  species.  Also  found  at  Bilin, 
in  Bohemia,  Tarnowitz  in  Silesia,  and  other  places. 


COMPOUNDS    OF    CALCIUM.  219 

Dolomite. — Calcium-Magnesium  Carbonate.     Magnesian  Carbonate  of 

Lime. 

Rhombohedral.     R  A  R= 106°  15'.     Cleavage  perfect  pa- 
rallel to  R.   Faces  of  rhombohedrons  sometimes 
curved,  AS  in  the  annexed  figure.   Often  granular 
and  massive,  constituting  extensive  beds. 

Color  white  or  tinged  with  yellow,  red,  green, 
brown,  and  sometimes  black.  Lustre  vitreous  or 
pearly.  Nearly  transparent  to  translucent.  Brit- 
tle. H.=3-5-4.  G.  =2  -8-2  -9. 

Co?nposition.  JCajMg  03  C  —  Calcium  carbonate  54'35, 
magnesium  carbonate  45 '65  =  100.  Some  iron  or  manga- 
nese is  often  present,  replacing  part  of  the  magnesium  or 
calcium.  Dolomite  resembles  calcite,  but  differs  in  that 
unless  finely  pulverized  it  effervesces  very  sparingly,  if  at 
all,  in  cold  dilute  hydrochloric  acid. 

The  princpal  varieties  of  this  species  arc  as  follows  : 

Dolomite.  White,  crystalline  granular,  often  not  distin- 
guishable in  external  characters  from  granular  limestone. 

Pearl  spar.     In  pearly  rhombohedrons  with  curved  faces. 

Rhomb  spar,  Broivn  spar.  In  rhombohedrons,  which  be- 
come brown  on  exposure,  owing  to  their  containing  5  to  10 
per  cent,  of  oxide  of  iron  or  manganese. 

A  cobaltiferous  variety  has  a  red  tint.  A  white  compact 
siliceous  variety  has  been  called  Gurhqfite.  Some  hydraulic 
limestones  are  dolomite. 

Dijf.  Distinctive  characters  nearly  the  same  as  for  cal- 
cite. It  is  harder  than  that  species,  and  differs  in  the 
angles  of  its  crystals,  and  effervesces  much  less  freely ;  but 
chemical  analysis  is  often  required  to  distinguish  them. 

Obs.  Massive  dolomite  is  common  in  Western  New  Eng- 
land and  Southeastern  New  York,  and  constitutes  much 
of  the  marble  used  for  building.  Crystallized  specimens 
are  obtained  at  the  Quarantine,  Richmond  County,  N.  Y. 
Rhomb  spar  occurs  in  talc,  at  Smithfield,  R.  I. ;  Marlboro', 
Vt;  Middlefield,  Mass. ;  pearl  spar  in  crystals  of  the  above 
form  at  Lockport,  Niagara  Falls,  Rochester,  Glen's  Falls ; 
gurhofite  on  Hustis's  farm,  Phillipstown,  N.  Y. 

Dolomite  was  named  in  honor  of  the  geologist  and  trav- 
eler, Dolomieu. 

Dolomite  burns  to  quicklime  like  calcite,  and  affords  a 
more  durable  cement.  The  white  massive  variety  is  used 


220 


DESCRIPTIONS   OF   MINERALS. 


extensively  as  marble.  The  magnesian  lime  has  been  sup- 
posed to  injure  soils  ;  but  this  is  believed  not  to  be  the  case 
if  it  is  air-slaked  before  being  used.  It  is  also  employed  in 
the  manufacture  of  Epsom  salts  or  magnesium  sulphate. 

Ankerite.  Resembles  brown  spar,  and,  like  that,  becomes  brown  on 
exposure.  Fundamental  from  a  rhombohedron  of  100°  12'.  It  is  a 
calcium-magnesium-iron-and-manganese  carbonate.  The  Styrian  iron 
ore  beds  of  Saltzburg  are  some  of  its  foreign  localities.  It  occurs  in 
Nova  Scotia,  and  in  quartz  veins  in  Western  New  Hampshire  ;  Quebec, 
Canada,  etc. 

Hydrodolomite.  A  calcium-magnesium  carbonate  containing  water. 
Pennite  from  Texas,  Pa.,  is  similar. 

BARIUM  AND  STRONTIUM. 

Barium  and  strontium  occur  in  nature  only  in  anhydrous 
ternary  compounds  of  the  following  kinds  :  sulphate,  car- 
bonate, silicate  ;  and  in  silicates  only  in  combination  with 
other  basic  elements.  The  species  are  characterized  by  high 
specific  gravity,  ranging  from  3*5  to  4  -8.  Strontium  gives 
a  red  color  to  the  blowpipe  flame  ;  and  barium,  if  strontium 
and  other  basic  elements  are  absent,  a  characteristic  green 
color. 

Barite.  —  Heavy  Spar.     Barium  Sulphate. 

Trimetric.     In  modified  rhombic  and  rectangular  prisms, 

M/=101°  40';    0Ap  =141°  08'  ;    0Al£=m°  18'.      Crys- 

tals usually  tabular.  Massive 
varieties  often  coarse  lamellar  ; 
also  columnar,  fibrous,  granu- 
lar  and  compact.  Lustre  vitr< 
ous;  sometimes  pearly.  Coloi 
white  and  sometimes  tingec 
yellow,  red,  brown,  blue,  01 
dark  brown.  Transparent  of 
translucent.  H.=2'5-3'5.  Gr. 
=  4-3-4-7. 

Composition.  Ba  04  S, 
Sulphur  tri  oxide  34'3,  baryta 
G5'7=100.  Strontium  and  cal- 
cium are  sometimes  present  re- 
placing a  little  barium.  B.B. 
fuses  to  a  bead  which  reacts 
Imparts  a  green  color  to  the  flame.  After  fusion 


1, 


alkaline. 


COMPOUNDS    OF    BARIUM    AND    STRONTIUM. 


221 


with  soda  in  the  reducing  flame  on  coal,  and  then  placed 
on  a  silver  coin  and  moistened,  it  produces  a  black  stain, 
due  to  sulphur. 

Barite  is  often  present  in  mineral  veins  as  the  gangue  of 
the  ore.  In  this  way  it  occurs  at  Cheshire,  Conn. ;  Hat- 
field,  Mass.  ;  Rossie  and  Hammond,  New  York ;  Perkio- 
men,  Pennsylvania,  and  the  lead  mines  of  the  Mississippi 
Valley.  Scoharie,  and  Pillar  Point  near  Sackett's  Harbor, 
are  other  localities ;  also  near  Fredericksburg  and  elsewhere, 
Virginia  ;  Nova  Scotia,  etc.  The  variety  from  Pillar  Point 
receives  a  fine  polish  and  looks  like  marble,  the  colors  being 
in  bands  or  clouds. 

Heavy  spar  is  ground  up  and  used  to  adulterate  white 
lead.  When  white  lead  is  mixed  in  equal  parts  with  it, 
it  is  sometimes  called  Venice  white,  and  another  quality 
with  twice  its  weight  of  barite  is  called  Hamburg  white, 
and  another,  one-third  white  lead,  is  called  Dutch  white. 
When  the  material  is  very  white,  a  proportion  of  it  gives 
greater  opacity  to  the  color,  and  protects  the  lead  from 
being  speedily  blackened  by  sulphurous  vapors ;  and  these 
mixtures  are  therefore  preferred  for  certain  kinds  of  painting. 

Dreelite  is  a  barium-calcium  sulphate. 

Witherite. — Barium  Carbonate. 

Trimetric.  /A/— 118°  30'.  Cleavage  imperfect.  Also 
in  globular  -or  botryoidal  forms  :  often  massive,  and  either 
fibrous  or  granular.  The  mas- 
sive varieties  have  usually  a  yellow- 
ish or  grayish-white  color,  with  a 
lustre  a  little  resinous,  and  are 
translucent.  The  crystals  are  often 
white  and  nearly  transparent.  H. 
=3-4.  G.=:4-29-4-35.  Brittle. 

Composition.  Ba  03  C  =  Carbon 
dioxide  22-3,  baryta  77  '7  =  100.  B. 
B.  decrepitates  and  fuses  easily, 
tingeing  the  flame  green,  to  a  trans- 
lucent globule,  which  becomes 
opaque  on  cooling,  and  colors  a 
moistened  turmeric  paper  red. 
r Effervesces  in  hydrochloric  acid. 
,  ^  Diff.  Distinguished  by  its  spe- 
cific gravity  and  fusibility  from  calcite  and  aragonite;  its 


DESCRIPTIONS    OP  MINERALS. 


action  with  acids,  from  allied  minerals  that  are  not  carbon- 
ates ;  by  yielding  no  metal,  from  cerussite,  and  by  tingeing 
the  flame  green,  from  strontianite. 

Obs.  The  most  important  foreign  localities  of  witherite 
are  at  Fallowfield  in  Northumberland  (where  it  is  mined). 
Alstonmoor  in  Cumberland,  and  Anglezark  in  Lancashire. 
It  is  also  found  in  Silesia,  Styria,  and  Sicily.  In  the  United 
States  it  occurs  at  Lexington,  Ky. 

Witherite-,  from  Fallowfield,  is  used  in  chemical  works,  in 
the  manufacture  of  plate  glass,  and  in  France  in  the  manu- 
facture of  beet  sugar. 

Barytocalcite,  Occurs  at  Alstonmoor  in  Cumberland,  England,  in 
•whitish  monoclinic  crystals.  H.=4  G.  =3  6-3 '7.  It  is  a  barium- 
calcium  carbonate. 

Bromlite  is  a  trimetric  mineral,  of  the  same  composition,  from 
Bromley  Hill,  near  Alston,  and  from  Northumberland,  England. 

Celestite. — Strontium  Sulphate. 

Trimetric.  /A/=103°  30'  to  104°  30'.  Crystals  rhombic 
prisms  or  tabular  ;  often  long  and  slender.  Cleavage  dis- 
tinct parallel  with  /.  Mas- 
sive varieties  :  columnar  or 
fibrous,  forming  layers  half 
an  inch  or  more  thick  with 
a  pearly  lustre  ;  rarely  gran- 
ular. Color  -generally  a 
tinge  of  blue,  but  sometimes 
clear  white  or  reddish.  Lus- 

tr^  vitreous  or  a  little  pearly ;  transparent  to  translucent. 
R.  =  3-3-5.  G.  =3-9-4.  Very  brittle. 

Composition.  Sr  04S=Sulphur  trioxide  43'6,  strontia 
56  '4:=  100.  B.B.  decrepitates  and  fuses,  tinging  the  flame 
bright  red  to  a  milk-white  alkaline  globule,  which  gives 
an  alkaline  reaction.  With  soda  on  coal  fuses  to  a  mass 
which  when  moistened  blackens  silver. 

Diff.  From  barite,  which  it  resembles,  it  is  distinguished 
by  the  bright  red  color  it  imparts  to  the  blowpipe  flame,  and 
its  less  specific  gravity  ;  and  from  the  carbonates,  by  not  ef- 
fervescing with  acids. 

Obs.  Celestite  is  found  in  beds  of  sandstone  or  lime- 
stone, and  also  with  gypsum,  rock  salt,  and  clay.  A  bluish 
celestine,  in  tabular  and  prismatic  crystals,  occurs  at  Stron- 
tian  Island,  Lake  Erie ;  Scoharie,  Lockport  and  Kossie, 


COMPOTTKDS   OF   TCTASSIUM   AKD   SODIUM.  #23 

Y.,  are*other  localities.  A  handsome  fibrous  variety  occurs 
at  Franktown,  Huntingdon  County,  Pennsylvania.  Sicily 
affords  fine  crystallizations  associated  with  sulphur. 

The  pale  sky-blue  tint,  so  common  with  the  mineral,  gave 
origin  to  the  name  celestite. 

Celestite  is  used  in  the  arts  for  making  the  nitrate  of 
strontia,  which  is  employed  for  producing  a  red  color  in  fire- 
works. 

Strontianite . — Strontium  Carbonate. 

Trimetric.  /A/=117°  19'.  Cleavage  parallel  to/,  near- 
ly perfect.  Occurs  also  fibrous  and  granular,  and  sometimes 
in  globular  shapes  with  a  radiated  structure  within. 
•  Color  often  a  light  tinge  of  green ;  also  white,  gray,  and 
yellowish  brown.  Lustre  vitreous,  or  somewhat  resinous. 
Transparent  to  translucent.  H.  =  3-5-4.  G.  =3-6-3 '72. 
Brittle. 

Composition.  Sr  03  C  =  Carbon  dioxide  29  '7,  strontia 
7O3—  100.  A  small  part  of  the  strontium  is  often  replaced 
by  calcium.  13. B.  swells,  throws  out  little  sprouts,  but 
does  not  fuse.  Colors  the  flame  bright  red,  and  after  heat- 
ing possesses  an  alkaline  reaction.  Effervesces  in  cold  di- 
lute acid ;  sulphuric  acid  gives  a  precipitate  of  strontium 
sulphate. 

Diff.  Its  effervescence  with  acids  distinguishes  it  from 
minerals  that  are  not  carbonates ;  the  color  of  the  flame 
before  the  blowpipe,  from  witherite  and  all  other  carbon- 
ates ;  calcium  salts  also  give  a  red  color  to  the  flame,  but 
the  shade  is  yellowish,  and  less  brilliant. 

Obs.  Strontianite  occurs  in  limestone  at  Scoharie,  N".  Y., 
in  crystals,  and  also  fibrous  and  massive ;  and  in  Jeffer- 
son County,  N.  Y.,  and  Mifflin  County,  Penn.  Strontian 
in  Argyleshire,  England,  was  the  first  locality  known,  and 
gave  the  name  to  the  mineral  and  the  metal  strontium.  It 
occurs  there,  with  galenite,  in  stellated  and  fibrous  groups 
and  in  crystals. 

This  mineral  is  used  for  preparing  the  strontium  nitrate. 

POTASSIUM  AND  SODIUM. 

Potassium  and  sodium  occur  in  nature  in  the  state  of 
chloride,  sulphate,  nitrate,  and  carbonate,  and  are  constitu- 
ents in  many  silicates. 


224  DESCRIPTIONS   OF   MINERALS. 

Sylvite. — Potassium  Chloride. 

Isometric.  White  or  colorless,  with  vitreous  lustre,  and 
taste  nearly  that  of  common  salt.  The  crystals  are  often 
cubes  with  octahedral  planes,  like  fig.  8  on  p.  19.  II. —2. 
G.=  1-9-2. 

Composition.  K  01= Chlorine  47'5,  potassium  52 '5  =  100. 
From  Vesuvius,  about  the  f  umaroles  of  the  volcano. 

Halite.— Common  Salt.     Sodium  Chloride. 

Isometric.  In  cubes  and  other  related  forms.  Some- 
times crystals  have  the  shape  of  a  shallow  four-sided  cup, 
and  are  called  hopper-shaped  crystals  ;  they  were  formed 
floating,  the  cup  receiving  its  enlargement  at  the  margin, 
this  being  the  part  which  lay  at  the  surface  of  the  brine 
where  evaporation  was  going  on.  Cleavage  cubic,  perfect. 

Color  usually  white  or  grayish,  sometimes  rose-red,  yel- 
low, and  of  amethystine  tints.  Taste  saline.  II.  =2.  G.= 
2-257. 

Composition.  Na  Cl=  Chlorine  60'7,  sodium  39'3  =  100. 
Crackles  or  decrepitates  when  heated  ;  fuses  easily,  coloring 
the  flame  deep  yellow. 

Diff.  Distinguished  by  its  taste,  solubility,  and  blowpipe 
characters. 

Obs.  Salt  occurs  in  extensive  but  irregular  beds,  usually 
associated  with  gypsum,  anhydrite,  and  clays  or  sandstone. 
It  occurs  in  formations  of  .all  ages,  from  the  Silurian  to  the 
present  time.  It  exists  in  the  Pyrenees,  in  the  valley  of 
Cardona  and  elsewhere,  forming  hills  300  to  400  feet  high ; 
in  Poland  and  Wieliczka  ;  at  Hall  in  the  Tyrol,  and  along  a 
range  through  Reichcnthal  in  Bavaria,  Halleinin  Saltzburg, 
Hallstadt,  Ischl  and  Ebensee  in  Upper  Austria,  and  Aussee 
in  Styria  ;  in  Hungary  at  Marmoros  and  elsewhere  ;  in 
Transylvania,  Wallachia,  Galicia  and  Upper  Silesia  ;  at 
Vic  and  Dieuze  in  France  ;  at  Bex  in  Switzerland  ;  in 
Cheshire,  England  ;  in  Northern  Africa  in  vast  quantities 
forming  hills  and  extended  plains  ;  in  Northern  Persia  at 
Tiflis  ;  in  India  in  the  province  of  Lahore,  and  in  the  valley 
of  Cashmere  ;  in  China  and  Asiatic  Russia;  in  South  Amer- 
ica, in  Peru  and  the  Cordilleras  of  New  Granada. 

Among  the  most  remarkable  deposits  are  those  of  Poland 
and  Hungary.  The  former,  near  Cracow,  have  been  worked 
since  the  year  1251,  and  it  is  calculated  that  there  is  still 


COMPOUNDS   OF   POTASSIUM   AND   SODIUM.  225 

enough  salt  remaining  to  supply  the  whole  world  for  many 
centuries.  Its  deep  subterranean  regions  are  excavated  into 
houses,  chapels  and  other  ornamental  forms,  the  roof  being 
supported  by  pillars  of  salt  ;  and  when  illuminated  by  lamps 
and  torches,  they  are  objects  of  great  splendor. 

The  salt  is  often  impure  with  clay,  and  is  purified  by  dis- 
solving it  in  large  chambers,  drawing  it  off  after  it  has 
settled,  and  evaporating  it  again.  The  salt  of  Norwich  (in 
Cheshire)  is  in  masses  5  to  8  feet  in  diameter,  which  are 
nearly  pure,  and  it  is  prepared  for  use  by  crushing  it  be- 
tween rollers. 

In  North  America,  beds  of  rock  salt  exist  at  Goderich  in 
Canada  ;  at  Wyoming  in  Western  New  York  (reached  by 
boring  to  a  depth  of  1,279  feet)  ;  in  Washington  County,  in 
Virginia;  and  extensively  at  Petite  Anse  in  Louisiana,  where 
it  underlies  144  acres  ;  in  Nevada,  at  several  localities  ;  in 
Ihe  Salmon  River  Mountains,  Oregon. 

Brine  springs  also  proceed  from  rocks  of  various  ages; 
and  often  they  are  indications  of  deep-seated  beds  of  rock 
salt. 

The  salt  of  Western  New  York,  and  Goderich,  Canada, 
is  of  the  Salina  period  of  the  Upper  Silurian  ;  the  brine 
springs  of  Michigan,  from  shales  and  marly tes  of  the  Sub- 
carboniferous  period  ;  those  of  the  salt  beds  of  Norwich, 
England,  in  magnesian  limestone  of  the  Permian  ;  those  of 
the  Vosges  and  of  Saltzburg,  Ischl,  and  the  neighboring 
regions,  in  marly  sandstone  of  the  Triassic  ;  those  of  Bex, 
in  Switzerland,  in  the  Lias  formation;  that  of  Wieliczka, 
Poland,  and  the  Pyrenees,  in  the  Cretaceous  or  chalk  forma- 
tion; that  of  Catalonia,  in  the  Tertiary  ;  that  of  Louisiana, 
in  the  Quaternary,  and  large  deposits  are  still  more  recent  ; 
and  besides  there  are  lakes  that  are  now  evaporating  and 
Producing  salt  depositions. 

Vast  lakes  of  salt  water  exist  in  many  parts  of  the  world. 
The  Great  Salt  Lake  of  Utah  has  an  area  of  2,000  square 
miles,  and  is  remarkable  for  its  extent,  considering  that  it 
is  situated  toward  the  summit  of  the  Rocky  Mountains,  at 
an  elevation  of  4,200  feet  above  the  sea.  Its  waters  contain 
^<)  per  cent,  of  sodium  chloride  (common  salt).  The  dry 
regions  of  these  mountains  and  of  Southwestern  California 
are  noted  for  salt  licks  and  lakes.  In  Northern  Africa 
large  lakes  as  well  as  hills  of  salt  abound,  and  the  deserts 
of  this  region  and  Arabia  abound  in  saline  efflorescences. 


226  DESCRIPTIONS   OF   MINERALS. 

The  Dead  and  Caspian  Seas,  and  the  lakes  of  Khoordistan, 
are  salt.  From  20-26  per  cent,  of  the  weight  of  the  water 
from  the  Dead  Sea  are  solid  salts,  of  which  10  per  cent,  are 
common  salt  Over  the  pampas  of  La  Plata  and  Patagonia 
there  are  many  ponds  and  lakes  of  salt  water. 

The  greater  part  of  the  salt  made  in  this  country  is  ob- 
tained by  evaporation  from  salt  springs.  Those  of  Salina  and 
Syracuse  are  well  known  ;  and  many  nearly  as  valuable  are 
worked  in  Ohio  and  other  Western  States.  At  the  best  New 
York  springs  a  bushel  of  salt  is  obtained  from  every  40  gal- 
lons. But  the  discovery  of  rock  salt  at  Wyoming,  west  of 
Syracuse,  may  lead  to  further  discoveries,  which  will  make 
the  brines  of  New  York  of  comparatively  little  value.  To 
obtain  the  brine,  wells  from  50  to  150  feet  deep  are  sunk  by 
boring.  It  is  then  raised  by  machinery. 

The  process  of  evaporation  under  the  heat  of  the  sun  is 
extensively  employed  in  hot  climates  for  making  salt  from 
sea  water,  which  affords  a  bushel  for  every  300  or  350  gal- 
lons. For  this  purpose  a  number  of  large  shallow  basins 
are  made  adjoining  the  sea  ;  they  have  a  smooth  bottom  of 
clay,  and  all  communicate  with  one  another.  The  water  is 
let  in  at  high  tide  and  then  shut  off  for  the  evaporation  to 
go  on.  This  is  the  simplest  mode,  and  is  used  even  in  un- 
civilized countries,  as  among  the  Pacific  Islands. 

Mirabilite.— Glauber  Salt.    Hydrous  Sodium  Sulphate. 

Monoclinic.  Occurs  in  efflorescent  crusts  of  a  white  or 
yellowish-white  color  ;  also  in  many  mineral  waters.  Taste 
cool,  then  feebly  saline  and  bitter. 

Composition.  Na2  04  S  4-  lOaq  =  Sulphur  trioxide  24 '8, 
soda  19-3,  water  55-9  =  100. 

Diff.  It  is  distinguished  from  Epsom  salt,  for  which  it 
is  sometimes  mistaken,  by  its  coarse  crystals,  and  the  yel- 
low color  it  gives  to  the  blowpipe  flame. 

It  is  made  in  enormous  amounts  from  common  salt,  its 
production  being  one  stage  in  the  manufacture  of  sodium 
carbonate.  It  is  used  in  medicine,  and  is  known  by  the 
familiar  name  of  "  salts." 

Obs.  On  Hawaii,  one  of  the  Sandwich  Islands,  in  a  cave 
at  Kailua,  Glauber  salt  is  abundant,  and  is  constantly  form- 
ing. It  is  obtained  by  the  natives  and  used  as  medicine. 
Glauber  salt  occurs  in  efflorescences  on  the  limestone  below 


COMPOUNDS  OP   POTASSIUM   AND   SODIUM.  227 

Genesee  Falls,  near  Rochester,  N.Y.    It  is  also  obtained  in 
Austria,  Hungary,  and  elsewhere  in  Europe. 

The  artificial  salt  was  first  discovered  by  a  German 
chemist  by  the  name  of  Glauber. 

AphtMtalite  (Arcanite).  Potassium  sulphate,  K204S= Sulphate  trL 
oxide  45'9,  potash  54*  1=100.  Found  at  Vesuvius.  Misenite  is  a  hy- 
drous potassium  sulphate  from  a  cavern  near  Misene. 

Thenardite.  Sodium  sulphate  N  a,  04S= Sulphur  trioxide  437, 
soda  56-3=100.  From  Spain,  Bolivia,  Tarapaca,  in  Peru;  Slate  Range, 
San  Bernardino  Co. ,  California  ;  and  in  Nevada. 

Glauberite.  Sodium-calcium  sulphate.  In  monoclinic  crystals,  at 
Villa  Rubia,  in  New  Castile,  Aussee,  in  Austria,  and  other  salt  beds. 

Poli/halite  and  Picromeride  are  hydrous  magnesium-potassium  sul- 
phates ;  Blazdite  and  Loweite  hydrous  magnesium-sodium  sulphates  ; 
Syngenite,  a  hydrous  calcium-potassium  sulphate. 

Borax. — Hydrous  Sodium  Biborate.    Tinkal. 

Monoclinic.  In  oblique  rhombic  prisms  /A  7=87°.  Cleav- 
age parallel  with  i-i  perfect.  The  crystals  are  white  and 
transparent,  with  a  glassy  lustre.  H.  =2-2 '5.  G.  =1*716. 
Taste  sweetish-alkaline. 

Composition.  Na207B44-10aq= Boron  trioxide  36-6,  soda 
16-2,  water  47*2  =  100.  B.B.  swells  up  to  many  times  its 
bulk  and  becomes  opaque  white,  and  finally  fuses  to  a 
glassy  globule. 

01)S.  Borax  was  originally  brought  from  a  salt  lake  in 
Thibet,  where  it  is  dug  in  considerable  masses  from  the 
edges  and  shallow  parts  of  the  lakes.  The  holes  thus  made 
in  a  short  time  become  filled  again  with  borax.  The  crude 
borax  was  formerly  sent  to  Europe  under  the  name  of  tin- 
leal,  and  there  purified  for  the  arts.  It  has  also  been  found 
in  Peru  and  Ceylon.  It  has  been  extensively  made  from  the 
boracic  acid  of  the  Tuscan  lagoons  by  the  reaction  of  this 
acid  on  sodium  carbonate. 

Borax  occurs  under  like  circumstances  in  California  and 
Nevada,  or  is  manufactured  from  other  borates  in  solution 
or  in  the  solid  state.  Localities  in  California  are  Borax 
Lake  and  its  vicinity,  north  of  San  Francisco ;  also  near 
Walker's  Pass,  Sierra  Nevada;  at  Mono  and  Owens  Lakes, 
and  at  Death  Valley,  near  the  borders  of  Nevada ;  in 
the  Slate  Range,  in  San  Bernardino  County ;  and  in 
Nevada,  at  Little  Salt  Lake,  near  Ragtown,  on  the  Pacific 
Railroad,  and  at  Columbus  Marsh.  The  Columbus  Marsh, 
in  Nevada,  near  lat.  38°  5' N.  and  long.  118°  W.,  46  miles 


228  DESCRIPTIONS   OF   MINERALS. 

north  of  trail  from  Mono  Lake,  is  a  deposit,  10  miles  long 
by  7  wide,  of  borates  and  other  salts,  chiefly  borax,  calcium 
borate,  sodium  sulphate,  and  common  salt.  The  large  de- 
posits of  "  priceite"  in  Southern  Oregon,  and  of  ulexite,  in 
the  "  Cane  Spring  District,"  20  miles  west  of  San  Bernar- 
dino, and  at  the  Columbus  Marsh,  are  other  sources  of 
borax.  The  amount  of  borax  received  at  San  Francisco 
during  the  year  1876  was  5,180,910  pounds,  and  in  1877, 
4,154,209  pounds. 

Nitre. — Potassium  Nitrate. 

Trimetric.  In  modified  right  rhombic  prisms.  / :  1= 
118°  50'.  Usually  in  thin  white  sub  transparent  crusts,  and 
in  needleform  crystals  on  old  walls  and  in  caverns.  Taste 
saline  and  cooling.  H  =  2.  G=1'97. 

Composition.  K803N= Nitrogen  pentoxide  (N2  05)  53 '4, 
potash  46 '6.  Burns  vividly  on  a  live  coal. 

Diff.  Distinguished  readily  by  its  taste  and  its  vivid  ac- 
tion on  a  live  coal ;  and  from  sodium  nitrate,  which  it  most 
resembles,  by  its  not  becoming  liquid  on  exposure  to  the 
air. 

Nitre,  called  also  saltpetre,  is  employed  in  making  gun- 
powder, forming  75  to  78  per  cent,  in  shooting  powder,  and 
62  in  mining  powder.  The  other  materials  are  sulphur  (10 
per  cent,  for  shooting  powder  to  20  for  mining)  and  char- 
coal (12  to  14  for  shooting  powder  and  18  for  mining).  It 
is  also  extensively  used  in  the  manufacture  of  nitric  and 
sulphuric  acids  ;  also  for  pyrotechnic  purposes,  fulminating 
po\vders,  and  sparingly  in  medicine. 

Obs.  Occurs  in  many  of  the  caverns  of  Kentucky  and 
other  Western  States,  scattered  through  the  earth  that 
forms  the  floor  of  the  cave.  In  procuring  it,  the  earth  is 
lixiviated,  and  the  lye,  when  evaporated,  yields  the  nitre. 
India  is  its  most  abundant  locality,  where  it  is  obtained 
largely  for  exportation. 

Spain  and  Egypt  also  afford  large  quantities  of  nitre  for 
commerce.  This  salt  forms  on  the  ground  in  the  hot  weather 
succeeding  copious  rains,  and  appears  in  silky  tufts  or  efflo- 
rescences ;  these  are  brushed  up  by  a  kind  of  broom,  lixi- 
viated, and  after  settling,  evaporated  and  crystallized.  In 
France,  Germany,  Sweden,  Hungary,  and  other  countries, 
there  are  artificial  arrangements  called  nitriaries  or  nitre 
beds,  from  which  nitre  is  obtained  by  the  decomposition 


COMPOUNDS   OF   POTASSIUM   AND   SODIUM.  £29 

mostly  of  the  nitrates  of  lime  and  magnesia  which  form  in 
these  beds.  Refuse  animal  and  vegetable  matter  putrefied 
in  contact  with  calcareous  soils  produces  nitrate  of  lime, 
which  affords  the  nitre  by  reaction  with  carbonate  of  pot- 
ash. Old  plaster  lixiviated  affords  about  5  per  cent.  This 
last  method  is  much  used  in  France.  The  nitric  acid  of 
the  cavern  nitrates  comes  from  the  atmosphere,  which  also 
consists  of  nitrogen  and  oxygen  ;  but  the  combination  takes 
place  through  the  agency  of  a  peculiar  kind  of  microscopic 
plant. 

Nitratine.— Soda  Nitre.    Sodium  Nitrate.    Cubic  Nitre. 

Rhombohedral  ;  R  :  R= 106°  33'.  Also  in  crusts  or  efflo- 
rescences, of  white,  grayish  and  brownish  colors.  Taste 
cooling.  Soluble  and  very  deliquescent. 

Composition.  Ha*  03N= Nitrogen  pentoxide  63-5,  soda 
36'5  — 100.  Burns  vividly  on  coal,  with  a  yellow  light. 

Diff.  It  resembles  nitre  (saltpetre),  but  deliquesces,  and 
gives  a  deep  yellow  light  when  burning. 

Obs.  In  the  district  of  Tarapaca,  Northern  Chili,  the 
dry  Pampa  for  an  extent  of  forty  leagues  is  covered  with 
heds  of  this  salt,  mixed  with  gypsum,  common  salt,  glauber 
salt,  and  remains  of  recent  shells. 

It  is  used  extensively  in  the  manufacture  of  nitric  acid. 
It  is  also  used  in  making  nitre  by  replacing  the  sodium  by 
potassium.  In  1866,  one  million  quintals  of  this  salt  were 
exported  from  Chili. 

Natron. — Hydrous  Sodium  Carbonate.     Carbonate  of  Soda. 

Monoclinic.  Generally  in  white  efflorescent  crusts,  some- 
times yellowish  or  grayish.  Taste  alkaline.  Effloresces  on 
exposure,  and  the  surface  becomes  white  and  pulverulent. 

Composition.    Na203  C  4-1  Oaq  =  Carbon  dioxide  26 '7,  soda 
1S'8,  water  54*5  =  100.     Effervesces  strongly  with  acids. 
*  Diff.  Distinguished  from  other   soda  salts   by  efferves- 
cing, and  from  trona,  by  efflorescing  on  exposure. 

Obs.  This  salt  is  found  in  solution  in  certain  waters, 
from  which  it  is  crystallized  in  efflorescences  by  evapora- 
tion. Abundant  in  the  soda  lakes  of  Egypt ;  also  in  lakes 
at  Debreezin,  in  Hungary ;  in  Mexico,  north  of  Zacatecas, 
and  elsewhere.  Sparingly  dissolved  in  the  Seltzer  and 
Carlsbad  waters. 


230  DESCRIPTIONS   OF   MINERALS. 

This  salt  (but  the  artificially  prepared)  is  extensively 
used  in  the  manufacture  of  soap  and  glass,  and  for  many 
other  purposes. 

Trona.  A  hydrous  sodium  sesquicarbonate  occurs  in  the  province 
of  Suckenna,  in  Africa,  between  Tripoli  and  Fezzan,  where  it  forms  a 
fibrous  layer  an  inch  thick  beneath  the  soil.  It  is  abundant  at  a  lake 
in  Maracaibo,  48  miles  from  Mendoza ;  and  forms  an  extensive  bed  in 
Churchill  County,  Nevada. 

Thermonatrite.  A  hydrous  sodium  carbonate  of  the  formula  Naa 
O3C+aq.  An  anhydrous  sodium  carbonate  is  stated  to  exist  native. 

Gay-Lus&ite.  Occurs  in  white  brittle  monoclinic  crystals.  Com- 
position ^Na|CaO3C+2iaq.  From  Lagunilla,  in  Maracaibo,  and  Lit- 
tle Salt  Lake,  near  Ragtown,  in  Nevada. 

AMMONIUM. 

The  salts  of  ammonia  are  more  or  less  soluble  in  water, 
and  are  entirely  and  easily  volatilized  before  the  blowpipe. 
When  treated  with  caustic  lime  or  potassa,  ammonia  is  lib- 
erated, and  is  recognized  by  its  odor  and  the  reaction  of  the 
vapors  on  test  papers. 

Salmiak, — Sal  Ammoniac,  Ammonium  Chloride. 

Occurs  in  white  crusts  or  efflorescences,  often  yellowish 
or  gray.  Crystallizes  in  regular  octahedrons.  Translucent 
— opaque.  Taste  saline  and  pungent.  Soluble  in  three  parts 
of  water. 

Composition.  NH4  01= Chlorine  66'3,  ammonium  33*7= 
100.  Gives  oil  the  odor  of  ammonia  when  powdered  and 
mixed  with  quicklime. 

Obs.  Occurs  in  many  volcanic  regions,  as  at  Etna,  Vesu- 
vius, and  the  Sandwich  Islands,  where  it  is  a  product  of 
volcanic  action.  Occasionally  found  about  ignited  coal 
seams. 

The  sal  ammoniac  of  commerce  is  manufactured  from 
animal  matter  or  coal  soot.  It  is  generally  formed  in  chim- 
neys of  both  wood  and  coal  fires.  In  Egypt,  whence  the 
greater  part  of  this  salt  was  formerly  obtained,  the  fires  of 
the  peasantry  are  made  of  the  dung  of  camels  ;  and  the  soot 
which  contains  a  considerable  portion  of  the  ammoniacal 
salt  is  preserved  and  carried  in  bags  to  the  works,  where  it 
is  obtained  by  sublimation.  Bones  and  other  animal  mat- 
ters are  used  in  Erance.  A  liquid  condensed  in  the  gas 
works,  is  also  used  in  its  production. 


WATER.  231 

It  is  a  valuable  article  in  medicine,  and  is  employed  by 
tinmen  in  soldering  to  prevent  the  oxidation  of  copper  sur- 
faces ;  also  in  a  variety  of  metallurgical  operations. 

Mascagnite.  A  hydrous  ammonium  sulphate.  In  mealy  crusts, 
of  a  yellowish-gray  or  lemon-yellow  color  ;  translucent  ;  taste  pungent 
and  bitter.  Composition  (N  H4)2O4  S  +  H.,0 = Sulphur  trioxide  53'3, 
ammonia  22  '8,  water  23 '9.  Easily  soluble  in  water.  Occurs  at  Etna, 
Vesuvius,  and  the  Lipari  Islands.  It  is  one  of  the  products  from  the 
combustion  of  anthracite  coal. 

Lecontite  is  hydrous  ammonium-sodium  sulphate.  Boussingaultite 
is  a  hydrous  ammonium-magnesium  sulphate,  from  Tuscany. 

Struvite.  A  hydrous  ammonium-magnesium  phosphate  ;  occurring 
in  yellowish  crystals,  slightly  soluble  in  water  ;  found  on  the  site 
of  an  old  church  in  Hamburg,  where  there  had  been  quantities  of  cat- 
tle dung. 

Tschermigite.  An  ammonia  alum  from  Tschermig,  Bohemia,  and 
Utah  County,  Utah 

Larderellite.  A  white  tasteless  ammonium  borate,  from  the  Tuscan 
lagoons. 

Hydrous  ammonium  phosphate  and  Ammonium  bicarbonate  (Tcsche- 
macherite)  have  been  detected  in  guano  ;  also,  Hydrous  sodium-am- 
monium phosphate,  called  Stercorite. 

HYDROGEN. 

Hydrogen  is  the  basic  constituent  in  hydrochloric  acid, 
and  in  water. 

Hydrochloric  Acid. — Muriatic  Acid. 

A  gas,  consisting  of  Chlorine  97'26,  hydrogen  2-74=100 
=  H  01.  It  has  a  pungent  odor,  and  is  acrid  to  the  skin. 

It  is  rapidly  dissolved  by  water.  If  passed  into  a  solution 
of  nitrate  of  silver,  it  produces  a  white  precipitate  which 
soon  blackens  on  exposure.  It  is  given  out  whenever  com- 
mon salt  is  acted  on  by  sulphuric  acid,  and  occasionally  by 
volcanoes. 

WATER. 

Water  (hydrogen  oxide)  is  the  well-known  liquid  of 
streams  and  wells.  The  purest  natural  water  is  obtained  by 
melting  snow,  or  receiving  rain  in  a  clean  glass  vessel  ;  but  it 
is  absolutely  pure  only  when  procured  by  distillation.  It 
consists  of  hydrogen  1  part  by  weight,  and  oxygen  8  parts, 
or  hydrogen  ll'll,  oxygen  88'89  =  i'00.  It  becomes  solid  at 
.32°  Fahrenheit  (or  6°  Centigrade),  and  then  crystallizes, 
and  constitutes  ice  or  snow.  The  crystals  are  of  the  hex- 
agonal system.  Flakes  of  snow  consist  of  a  congeries  of 


232  DESCRIPTIONS   OP   MINERALS. 

minute  crystals,  and  stars,  like  the  figures  on  page  4,  may 
often  be  detected  with  a  glass.  Various  other  allied  forms 
are  also  assumed.  The  rays  meet  at  an  angle  of  60°,  and 
the  branchlets  pass  off  at  the  same  angle  with  perfect  regu- 
larity. The  density  of  water  is  greatest  at  39°  2'  F.;  below 
this  it  expands  as  it  approaches  32°,  owing  to  incipient 
crystallization,  and  in  the  state  of  ice  it  is  only  0-920.  It 
boils  at  212°  F.  A  cubic  inch  of  pure  water  at  62°  F.  and  30 
inches  of  the  barometer,  weighs  252*458  grains,  which  equals 
16'386  grams;  and  a  cubic  foot  of  water  weighs  62-355 
pounds  avoirdupois.  A  pint,  United  States  standard  mea- 
sure, holds  just  7,342  troy  grains  of  water,  which  is  little 
above  a  pound  avoirdupois  (7,000  grains  troy). 

Water,  as  it  occurs  on  the  earth,  contains  some  atmo- 
spheric air,  without  which  the  best  would  be  unpalatable. 
This  air,  with  some  free  oxygen  also  present,  is  necessary 
to  the  life  of  aquatic  animals.  In  most  spring  water  there 
is  a  minute  proportion  of  salts  of  calcium  (sulphate,  chloride 
or  carbonate),  often  with  a  trace  of  common  salt,  carbonate 
of  magnesium  and  some  alumina,  iron,  silica, phosphoric  acid, 
carbonic  acid,  and  certain  vegetable  acids.  These  impuri- 
ties constitute  usually  from  -fa  to  10  parts,  in  10,000  parts 
by  weight.  The  water  of  Long  Pond,  near  Boston,  con- 
tains about  £  a  part  in  10,000  ;  the  Schuylkill  of  Philadel- 
phia, about  1  part  in  10,000  ;  the  Croton,  used  in  New  York 
city,  1  to  1^  parts  in  10,000.  Nitric  acid  is  usually  found 
in  rain  water  combined  with  ammonia  ;  river  waters  are 
ordinarily  the  purest  of  natural  waters,  unless  they  have 
flowed  through  a  densely  populated  region. 

Sea  water  contains  from  32  to  37  parts  of  solid  substances 
in  solution  in  1,000  parts  of  water.  The  largest  amount  in 
the  Atlantic,  36*6  parts,  is  found  under  the  equator,  away 
from  the  land  or  the  vicinity  of  fresh-water  streams  ;  and 
the  smallest  in  narrow  straits,  as  Dover  Straits,  where  there 
are  only  32-5  parts.  In  the  Baltic  and  Black  Seas,  the  pro- 
portion is  only  one-third  that  in  the  open  ocean.  Of  the 
whole,  one-half  to  two-thirds  is  common  salt  (sodium  chlo- 
ride). The  other  ingredients  are  magnesium  salts  (chloride 
and  sulphate),  amounting  to  four-fifths  of  the  remainder, 
with  sulphate  and  carbonate  of  calcium,  and  traces  of  bro- 
mides, iodides,  phosphates,  borates  and  fluorides.  The  water 
of  the  British  Channel  affords  water  964'7  parts  in  1,000, 
sodium  chloride  27*1,  potassium  chloride  0'8,  magnesium 


SILICA.  233 

chloride  3 '7,  magnesium  sulphate  2*30,  calcium  sulphate 
1-4,  calcium  carbonate  0-03,  with  some  magnesium  bromide 
and  probably  traces  of  iodides,  fluorides,  phosphates  and 
borates.  The  bitter  taste  of  sea  water  is  owing  to  the  salts 
of  magnesium  present. 

The  waters  of  the  Dead  Sea  contain  200  to  260  parts  of 
solid  matter  in  1,000  parts  (or  20  to  26  per  cent),  including 
7  to  10  per  cent,  of  common  salt,  the  same  proportion  of 
magnesian  salts,  principally  the  chloride,  2£  to  3£  per  cent, 
of  calcium  carbonate  and  sulphate,  besides  some  bromides 
and  alumina.  The  density  of  these  waters  is  owing  to  this 
large  proportion  of  saline  ingredients.  The  brine  springs 
of  New  York  and  other  States  south  and  west,  are  well- 
known  sources  of  salt  (see  under  Common  salt).  Many  of 
the  springs  afford  bromine,  and  large  quantities  of  it  are 
manufactured  for  making  photographic  plates  and  for  other 
purposes. 

Mineral  waters  vary  much  in  constitution.  They  often 
contain  iron  in  the  state  of  bicarbonate,  like  those  of  Sara- 
toga and  Ballstown,  and  are  then  called  chalybeate  waters, 
from  the  ancient  name  for  iron  or  steel,  clialybs,  derived 
from  the  name  of  a  country  on  the  Baltic.  Hydrogen  sul- 
phide is  often  held  in  mineral  waters  and  imparts  to  them 
its  odor  and  taste ;  such  are  the  so-called  sulphur  springs. 

Minute  traces  of  salts  of  zinc,  arsenic,  lead,  copper,  an- 
timony and  tin,  have  been  found  in  some  waters.  What- 
ever is  soluble  in  a  region  through  which  waters  flow,  will 
of  course  be  taken  up  by  them,  and  many  ingredients  are 
soluble  in  minute  proportions,  which  are  usually  described 
as  insoluble. 


III.   SILICA  AND  SILICATES. 
I.  SILICA. 

Quartz. 

Rhombohedral.  Occurs  usually  in  six-sided  prisms,  more 
or  less  modified,  terminated  with  six-sided  pyramids  :  R/\R 
=94°  15'.  No  cleavage  apparent,  seldom  even  in  traces ; 
but  sometimes  obtained  by  heating  the  crystal  and  plunging 
it  into  cold  water.  Sometimes  in  coarse  radiated  forms; 


234 


DESCRIPTIONS   OF  MINERALS. 


also  coarse  and  fine  granular ;  also  compact,  either  amor- 
phous, or  presenting  stalactitic  and  rnammillary  shapes. 

Crystals  often  as  pellucid  as  glass,  and  colorless ;  some- 
times topaz-yellow,  amethystine,  rose,  smoky,  or  other  tints. 
Also  of  all  degrees  of  transparency  to  opaque,  and  of  various 
shades  of  yellow,  red,  green,  blue  and  brown  colors  to  black. 
In  some  varieties  the  colors  are  in  bands,  stripes,  or  clouds, 


1. 


2. 


5. 


Composition.  Si02=0xygen  53'33,  silicon  46-67  =  100. 
Opaque  varieties  often  contain  oxide  of  iron,  clay,  chlorite, 
or  some  other  mineral  disseminated  through  them.  B.B. 
infusible.  With  soda,  fuses  with  effervescence. 

Diff.  Quartz  is  exceedingly  various  in  color  and  form, 
but  may  be  distinguished,  by  (1)  absence  of  true  cleavage; 
(2)  its  hardness  ;  (3)  its  infusibility  before  the  blowpipe  ; 
(4)  its  insolubility  with  either  of  the  common  acids;  (5)  its 
effervescence  when  heated  B.B.  with  soda  ;  and  (6)  when 
crystallized,  by  the  forms  of  its  crystals,  which  are  almost 
always  six-sided  prisms  terminating  in  six-sided  pyramids. 

The  varieties  of  quartz  owe  their  peculiarities  either  to 
crystallization,  mode  of  formation,  or  impurities,  and  they 
fall  naturally  into  three  series. 

I.  The  vitreous  varieties)  distinguished  by  their  glassy 
fracture. 

II.  The  clialcedonic  varieties,  having  a  subvitreous  or  a 
waxy  lustre,  and  generally  translucent. 

III.  Thejaspery  cryptocrystalline  varieties,  having  barely 
a  glimmering  lustre  or  none,  and  opaque. 

I.   VITREOUS  VARIETIES. 

Rock  Crystal.     Pure  pellucid  quartz. 

This  is  the  mineral  to  which  the  word  crystal  was  first 
applied  by  the  ancients  ;  it  is  derived  from  the  Greek  krus- 
tallos,  meaning  ice.  The  pure  specimens  are  often  cut  and 
used  in  jewelry,  under  the  name  of  '•'  white  stone." 

It  is   often   used  for  optical  instruments  and  spectacle 


SILICA.  235 

glasses,  and  even  in  ancient  times  was  made  into  cups  and 
vases.  Nero  is  said  to  have  dashed  to  pieces  two  caps  of 
this  kind  on  hearing  of  the  revolt  that  caused  his  ruin,  one 
of  which  cost  him  a  sum  equal  to  $3,000. 

Amethyst.  Purple  or  bluish-violet,  and  often  of  great 
beauty.  The  color  is  owing  to  a  trace  of  manganese  oxide. 
It  was  called  amethyst  on  account  of  its  supposed  preser- 
vative powers  against  intoxication.  When  finely  and  uni- 
formly colored,  highly  esteemed  as  a  gem. 

Rose  Quartz.  Pink  or  rose-colored.  Seldom  occurs  in 
crystals,  but  generally  in  masses  much  fractured,  and  im- 
perfectly transparent.  The  color  fades  on  exposure  to  the 
light,  and  on  this  account  it  is  little  used  as  an  ornamental 
stone,  yet  is  sometimes  cut  into  cups  and  vases. 

False  Topaz.  Light  yellow  pellucid  crystals.  They  are 
often  cut  and  set  for  topaz.  The  absence  of  cleavage  dis- 
tinguishes it  from  true  topaz.  The  name  citrine,  often  ap- 
plied to  this  variety,  alludes  to  its  yellow  color. 

Smoky  Quartz.  Crystals  of  a  smoky  tint ;  the  color  is 
sometimes  so  dark  as  to  be  nearly  black  and  opaque  except 
in  splinters.  It  is  the  cairngorm  stone. 

Milky  Quartz.  Milk-white,  nearly  opaque,  massive,  and 
of  common  occurrence.  It  has  often  a  greasy  lustre,  and  is 
then  called  greasy  quartz. 

Prase.  Leek-green,  massive  ;  resembling  some  shades  of 
beryl  in  tint,  but  easily  distinguished  by  the  absence  of 
cleavage  and  its  infusibility.  Supposed  to  be  colored  by  a 
trace  of  iron  silicate. 

Aventurine  Quartz.  Common  quartz  spangled  through- 
out with  scales  of  golden-yellow  mica.  It  is  usually  trans- 
lucent, and  gray,  brown,  or  reddish  brown  in  color. 

Ferruginous  Quartz.  Opaque,  and  either  of  yellow, 
brownish-yellow,  or  red  color.  The  color  is  due  to  the 
presence  of  iron  oxide  as  an  impurity,  the  red  to  the  anhy- 
drous oxide,  and  the  brownish  yellow  to  the  hydrous  oxide. 

H.    CHALCEDONIC    VARIETIES. 

Chalcedony.  Translucent,  massive,  with  a  glistening  and 
somewhat  waxy  lustre  ;  usually  of  a  pale  grayish,  bluish,  or 
light  brownish  shade.  Often  occurs  lining  or  filling  cavities 
in  amygdaloidal  rocks,  and  sometimes  in  other  kinds.  These 
cavities  are  nothing  but  little  caverns,  into  which  siliceous 
waters  have  filtrated  at  some  period.  The  stalactites  are 


236  DESCRIPTIONS   OP   MINERALS. 

"icicles"  of  chalcedony,  hung  from  the  roof  of  the  cavity. 
Some  of  these  chalcedony  grottos  are  several  feet  in  dia- 
meter. Large  geodes  of  this  kind  occur  in  the  Keokuk 
limestone  in  Illinois  and  Iowa. 

Chrysoprase.  Apple-green  chalcedony.  It  is  colored  by 
nickel. 

Carnelian.  A  bright  red  chalcedony,  generally  of  a  clear 
rich  tint.  It  is  cut  and  polished  and  much  used  in  the  more 
common  jewelry.  It  is  often  cut  for  seals  and  beads. 

Sard.  A  deep  brownish-red  chalcedony,  of  a  blood-red 
color  by  transmitted  light. 

Agate.  A  variegated  chalcedony.  The  colors  are  dis- 
tributed in  clouds,  spots,  or  concentric  lines.  These  lines 
take  straight,  circular,  or  zigzag  forms  ;  and  when  the  last 
it  is  called  fortification  agate,  so  named  from  the  resem- 
blance to  the  angular  outlines  of  a  fortification.  These  lines 
are  the  edges  of  la}rers  of  chalcedony,  and  these  layers  are 
the  successive  deposits  during  the  process  of  its  formation. 
Mocha  stone  or  Moss  agate  is  a  brownish  agate,  consisting 
of  chalcedony  with  dendritic  or  moss-like  delineations,  of  an 
opaque  yellowish-brown  color.  They  arise  from  dissem- 
inated iron  oxide.  All  the  varieties  of  agate  are  beautiful 
stones  when  polished,  but  are  not  much  used  in  fine  jewelry. 
The  colors  may  be  darkened  by  boiling  the  stone  in  oil,  and 
then  dropping  it  into  sulphuric  acid  ;  a  little  oil  is  absorbed 
by  some  of  the  layers,  which  becomes  blackened  or  charred 
by  the  acid. 

Onyx.  A  kind  of  agate  having  the  colors  arranged  in 
flat  horizontal  layers  ;  the  colors  are  usually  light  clear 
brown  and  an  opaque  white.  When  the  stone  consists  of 
sard  and  white  chalcedony  in  alternate  layers,  it  is  called 
sardonyx.  Onyx  is  the  material  used  for  cameos,  and  is 
well  fitted  for  this  kind  of  miniature  sculpture.  The  figure 
is  carved  out  of  one  layer  and  stands  in  relief  on  another. 
A  noted  ancient  cameo  is  the  Mantuan  vase  at  Brunswick. 
It  was  cut  from  a  single  stone,  and  has  the  form  of  a  cream- 
pot,  about  7  inches  high  and  2£  broad.  On  its  outside, 
which  is  of  a  brown  color,  there  are  white  and  yellow  groups 
of  raised  figures,  representing  Ceres  and  Triptolemus  in 
search  of  Proserpine. 

Cat's  Eije  is  greenish-gray  translucent  chalcedony,  hav- 
ing a  peculiar  opalescence,  or  glaring  internal  reflections, 
like  the  eye  of  a  cat,  when  cut  with  a  spheroidal  surface. 


SILICA.  237 

1'he  effect  is  owing  to  filaments  of  asbestus.  It  comes  from 
Ceylon  and  Malabar,  ready  cut  and  polished,  and  is  a  gem 
of  considerable  value. 

Flint,  Hornstone.  Massive  compact  silica,  of  dark  shades 
of  smoky  gray,  brown,  or  even  black,  and  feebly  translucent, 
it  breaking  with  sharp  cutting  edges  and  a  conchoidal  sur- 
face. Flint  occurs  in  nodules  of  chalk:  notunfrequently  the 
nodules  are  in  part  chalcedonic.  Hornstone  differs  from 
flint  in  being  more  brittle  ;  it  is  often  found  in  limestone. 

Chert  is  an  impure  hornstone.  Limestones  containing 
hornstone  or  chert  are  often  called  clierty  limestone. 

Plasma.  A  faintly  translucent  variety  of  chalcedony  ap- 
proaching jasper,  of  a  green  color,  sprinkled  with  yellow 
and  whitish  dots. 

III.     JASPERY    VARIETIES. 

Jasper.  A  dull  red  or  yellow  siliceous  rock,  containing 
some  clay  and  yellow  or  red  iron  oxide,  the  red,  the  anhy« 
drous  oxide,  ami  the  yellow,  the  hydrous  oxide.  Heat  drives 
off  the  water  from  the  yellow  jasper  and  turns  it  red.  It 
also  occurs  of  green  and  other  shades.  Riband  jasper  is  a 
jasper  consisting  of  broad  stripes  of  green,  yellow,  gray, 
red,  or  brown.  Egyptian  jasper  consists  of  these  colors  in 
irregular  concentric  zones,  and  occurs  in  nodules,  which 
are  often  cut  across  and  polished.  Ruin  jasper  is  a  variety 
with  delineations  like  ruins,  of  some  brownish  or  yellowish 
shade  on  a  darker  ground.  Porcelain  jasper  is  nothing  but 
a  baked  clay,  and  differs  from  jasper  in  being  fusible  before 
the  blowpipe.  Red  felsyte  resembles  red  jasper ;  but  this 
is  also  fusible,  and  consists  largely  of  feldspar. 

Jasper  admits  of  a  high  polish,  and  is  a  handsome  stone 
for  inlaid  work,  but  is  not  much  used  as  a  gem. 

Bloodstone  or  Heliotrope.  Deep  green,  slightly  trans- 
lucent, containing  spots  of  red,  which  have  some  resem- 
blance to  drops  of  blood.  It  contains  a  few  per  cent,  of 
clay  and  iron  oxide  mechanically  combined  with  the  silica. 
The  red  spots  are  colored  with  iron.  There  is  a  bust  of 
Christ  in  the  royal  collection  at  Paris,  cut  in  this  stone,  in 
which  the  red  spots  are  so  managed  as  to  represent  drops 
of  blood. 

Lydian  Stone,  Touchstone,  Basanite.  Velvet-black  and 
opaque,  and  used,  on  account  of  its  hardness  and  black 
color,  for  trying  the  purity  of  the  precious  metals ;  this  ia 


238  DESCRIPTIONS   OF   MINERALS. 

done  by  comparing  the  color  of  the  mark  left  on  it  with 
that  of  an  alloy  of  known  character.  The  effect  of  acids 
upon  the  mark  is  also  noted. 

Besides  the  above  there  are  other  varieties  arising  from 
structure. 

Tabular  Quartz.  Consists  of  thin  plates,  either  parallel 
or  crossing  one  another  and  leaving  large  open  cells. 

Granular  Quartz.  A  rock  consisting  of  quartz  grains 
compactly  cemented.  The  colors  are  white,  gray,  flesh-red, 
yellowish  or  reddish-brown.  It  is  a  hard  siliceous  sand- 
stone. Ordinary  sandstone  often  consists  of  nearly  pure 
quartz. 

Pseudomorplious  Quartz.  Quartz  under  the  forms  of  cal- 
cite,  barite,  fluorite  or  other  mineral.  Shells,  corals,  etc., 
are  sometimes  found  converted  into  quartz  by  the  ordinary 
process  of  petrifaction. 

Silicified  Wood.  Petrified  wood  often  consists  of  quartz, 
quartz  having  taken  the  place  of  the  original  wood.  Some 
specimens  are  petrified  with  chalcedony  or  agate. 

Penetrating  substances.  Quartz  crystals  are  sometimes 
penetrated  by  other  minerals.  Rutile,  asbestus,  actinolite, 
topaz,  tourmaline,  chlorite  and  epidote,  are  some  of  these 
substances.  The  rutile  often  looks  like  needles  or  find 
hairs  of  a  brown  color  passing  through  in  every  direc- 
tion. They  are  cut  for  jewelry,  and  in  France  pass  by  the 
name  of  Fleches  d*  amour  (love's  arrows).  The  crystals  of 
Herkimer  County,  N.  Y.,  often  contain  a  kind  of  black  coal. 
Other  crystals  contain  cavities  filled  with  some  fluid,  as 
water,  naphtha,  or  liquid  carbonic  acid,  or  with  minute 
crystals. 

Obs.  Quartz  is  an  essential  constituent  of  granite,  gneiss, 
mica  schist,  and  many  other  common  rocks,  and  the  chief 
or  only  constituent  of  many  sandstones,  and  of  the  sands 
of  most  sea-shores.  Fine  quartz  crystals  occur  in  Herki- 
mer County,  New  York,  at  Middlefield,  Little  Falls,  Salis- 
bury and  Newport,  in  the  soil  and  in  cavities  in  a  sand- 
stone. The  beds  of  iron  ore  at  Fowler  and  Hermon,  St. 
Lawrence  County,  afford  dodecahedral  crystals.  Diamond 
Island,  Lake  George,  Pelham  and  Chesterfield,  Mass.,  Paris 
and  Perry,  Me.,  Meadow  Mt.,  Md.,  and  Hot  Springs,  Ar- 
kansas, are  other  localities.  Rose  quartz  is  found  at  Albany 
and  Paris,  Me.,  Acworth,  N.  H.,  and  Southbury,  Conn.; 
quartz  at  Goshen,  Mass. ;  Paris,  Me. ;  in  North  Caro-. 


SILICA.  23ft 

lina ;  at  Pike's  Peak,  Colorado,  and  elsewhere  ;  amethyst  at 
Bristol,  R.  L,  and  Keweenaw  Point,  Lake  Superior  ;  chalce- 
dony and  agates  of  moderate  beauty  near  Northampton, 
and  along  the  trap  of  the  Connecticut  Valley — but  finer 
near  Lake  Superior,  upon  some  of  the  Western  rivers,  and 
in  Oregon  ;  chrysoprase  occurs  at  Belmont's  lead  mine,  St. 
Lawrence  County,  N.  Y.,  and  a  green  quartz  (often  called 
chrysoprase)  at  New  Fane,  Vt.,  along  with  fine  drusy 
quartz  ;  red  jasper  occurs  on  the  banks  of  the  Hudson  at 
Troy ;  yellow  jasper  is  found  with  chalcedony  at  Chester, 
Mass.  ;  Heliotrope  occupies  veins  in  slate  at  Bloomingrove, 
Orange  County,  N.  Y. 

Switzerland,  Dauphiny,  Piedmont,  the  Carrara  quarries, 
and  numerous  other  foreign  localities  furnish  fine  crystals. 

OpaL 

Compact  and  amorphous  ;  also  in  renif orm  and  stalactitic 
shapes  ;  also  earthy.  Presents  internal  reflections,  often  of 
several  colors  in  the  finest  varieties,  exhibiting,  when  turned 
in  the  hand,  a  rich  play  of  colors  of  delicate  shades.  White, 
yellow,  red,  brown,  green  and  gray  are  some  of  the  shades 
that  occur,  and  impure  varieties  are  dark  and  opaque. 
Lustre  subvitreous.  H.  =  5  '5-6  '5.  G .  =  1  '9-2-3. 

Composition.  Opal  consists  of  silica,  like  quartz;  but  it 
is  silica  in  a  different  molecular  state,  the  hardness  and 
specific  gravity  being  less;  and,  besides  this,  it  is  soluble  in 
a  strong  alkaline  solution,  especially  if  heated.  It  usually  con- 
tains a  few  per  cent,  of  water — amounting  in  some  kinds  to 
12  per  cent. ;  but  the  water  is  not  generally  regarded  as  an 
essential' constituent. 

VARIETIES. 

Precious  Opal.  External  color  usually  milky,  but  within 
there  is  a  rich  play  of  delicate  tints.  This  variety  forms  a 
gem  of  rare  beauty.  A  large  mass  in  the  imperial  cabinet 
of  Vienna  weighs  seventeen  ounces,  and  is  nearly  as  large 
as  a  man's  fist,  but  contains  numerous  fissures  and  is  not 
entirely  disengaged  from  the  matrix.  This  stone  was  well 
known  to  the  ancients  and  highly  valued  by  them.  They 
called  it  Paideros,  or  Child  Beautiful  as  Love.  The  noble 
opal  is  found  near  Cashau  in  Hungary,  and  in  Honduras, 
South  America  ;  also  on  the  Faroe  Islands. 

Fire  Opal,  Girasol.  An  opal  with  yellow  and  bright  hya- 


240  DESCRIPTIONS   OF  MINERALS. 

cinth  or  fire-red  reflections.  It  comes  from  Mexico  and  the 
Faroe  Islands. 

Common  Opal,  Semiopal.  Common  opal  has  the  hardness 
of  opal  and  is  easily  scratched  by  quartz,  a  character  which 
distinguishes  it  from  some  siliceous  stones  often  called  semi- 
opal.  It  has  sometimes  a  milky  opalescence,  but  does  not 
reflect  a  play  of  colors.  The  lustre  is  slightly  resinous,  and 
the  colors  are  white,  gray,  red,  yellow,  bluish,  greenish  to 
dark  grayish-green.  Translucent  to  nearly  opaque.  Phillips 
found  nearly  8  per  cent,  of  water  in  one  specimen. 

Hydrophane.  This  variety  is  opaque  white  or  yellowish 
when  dry,  but  becomes  translucent  and  opalescent  when 
immersed  in  water. 

Cacholong.  Opaque  white,  or  bluish  white,  and  usually 
associated  with  chalcedony.  Much  of  what  is  so  called  is 
nothing  but  chalcedony;  but  other  specimens  contain  water, 
and  are  allied  to  hydrophane.  It  contains  also  a  little  alu- 
mina and  adheres  to  the  tongue.  It  was  first  brought  from 
the  river  Oaoh  in  Bucharia. 

Hyalite,  Mullens  Glass.  A  glassy  transparent  variety,  oc- 
curring in  small  concretions  and  occasionally  stalactitic. 
It  resembles  somewhat  a  transparent  gum  arabic.  Composi- 
tion, Silica  92-00,  water  6-33  (Bucholz). 

Menilite.  A  brown  opaque  variety,  in  compact  reniform 
masses,  occasionally  slaty.  Composition,  Silica  85'5,  water 
11*0  (Klaproth).  It  is  found  in  slate  at  Menil  Montant, 
near  Paris. 

Wood  Opal.  An  impure  opal,  of  a  gray,  brown  or  black 
color,  having  the  structure  of  wood,  and  looking  much  like 
common  silicified  wood.  It  is  wood  petrified  with  a  hy- 
drated  silica  (or  opal),  instead  of  pure  silica,  and  is  distin- 
guished by  its  lightness  and  inferior  hardness.  Specific 
gravity,  2. 

Opal  Jasper.  Resembles  jasper  in  appearance,  and  con- 
tains a  few  per  cent,  of  iron  ;  but  it  is  not  so  hard,  owing  to 
the  water  it  contains. 

Siliceous  Sinter  has  often  the  composition  of  opal,  though 
sometimes  simply  quartz.  The  name  is  given  to  a  loose, 
porous  siliceous  rock  usually  of  a  grayish  color.  It  is  de- 
posited around  the  Geysers  of  Iceland  and  the  Yellowstone 
Park,  in  cellular  or  compact  masses,  sometimes  in  fibrous, 
stalactitic,  or  cauliflower-like  shapes.  It  is  often  called  gey- 
serite.  Pearl  sinter,  or  fiorite,  occurs  in  volcanic  tufa  in 


SILICA.  241 

smooth  and  shining  globular,  botryoidal  masses,  having  a 
pearly  lustre. 

Float  Stone.  A  variety  of  opal  having  a  porous  and  fibrous 
texture,  and  hence  so  light  that  it  will  float  011  water.  It 
occurs  in  concretionary  or  tuberose  masses,  which  often 
have  a  nucleus  of  quartz. 

Tripolite,  or  Infusorial  Earth.  A  white  or  grayish-white 
earth,  made  mainly  of  siliceous  secretions  of  microscopic 
plants  called  Diatoms.  It  forms  beds  of  considerable  extent, 
and  often  occurs  beneath  peat.  It  is  used  as  a  polishing 
powder  ;  also  to  mix  with  nitroglycerine  and  make  dynamite ; 
and,  owing  to  its  poor  conduction  of  heat,  it  is  applied  as  a 
protection  to  steam  boilers  and  pipes. 

Tabaslieer  is  a  siliceous  aggregation  found  in  the  joints  of 
the  bamboo  in  India.  It  contains  several  per  cent,  of  water, 
and  has  nearly  the  appearance  of  hyalite. 

Diff.  Infusibility  before  the  blowpipe  is  the  best  charac- 
ter for  distinguishing  opal  from  pitchstone,  pearlstone,  and 
other  species  it  resembles.  The  absence  of  anything  like 
cleavage  or  crystalline  structure  is  another  characteristic. 
Its  inferior  hardness  and  specific  gravity  separates  it  from, 
quartz. 

Obs.  Hyalite  occurs  sparingly  at  the  Phillips  ore  bed, 
Putnam  County,  N.  Y.,  and  in  Burke  and  Scriven  counties, 
Georgia.  In  Washington  County,  Ga.,  good  fire  opal  is 
obtained.  The  Suanna  Spring  in  Georgia  affords  small 
quantities  of  siliceous  sinter.  Tripolite  occurs  in  Maine, 
New  Hampshire,  Nevada,  California,  and  elsewhere. 

Tridymite.  Pure  silica,  like  quartz  and  opal,  with  very  nearly  the 
hardness  and  specific  gravity  of  opal,  but  occurring  in  tabular  hexag- 
onal prisms,  which  are  twins  under  the  triclinic  system.  If  not  crys- 
tallized opal,  it  is  a  third  state  of  Si02.  It  occurs  in  trachytic  and. 
some  other  volcanic  rocks.  Asmanite  is  from  a  meteorite,  and  may  be 
the  same  as  tridymite. 

Jenzschite.  Silica,  SiO,,  in,  it  is  supposed,  a  fourth  state,  it  resem- 
bling opal  in  aspect  and  in  solubility  in  alkaline  solutions,  but  having 
the  specific  gravity  of  quartz,  or  2  6.  From  Hiittenberg  in  Carinthia, 
resembling  a  white  cachalong ;  from  near  Weissig  ;  Regensberg  ;  and 
in  Brazil. 

Melanophlogite.  Colorless  cubes  consisting  of  silica,  with  a  little 
sulphuric  trioxide  and  water.  On  sulphur  from  Girgenti,  Sicily. 


242  DESCRIPTIONS   OF  MINERALS. 


II.  SILICATES. 

The  silicates  are  here  divided  into  the  anhydrous  and 
the  hydrous. 

In  part  of  the  anhydrous  silicates,  the  combining  value 
(or  quantivalence,  see  page  77)  of  the  silicon  is  to  that  of 
the  basic  elements  as  2  to  1  ;  in  another  part,  as  1  to  1  ; 
and  in  a  third  division,  as  less-than-1  to  1.  On  this  ground 
the  mineral  silicates  may  be  arranged  in  three  groups, 
named  respectively:  I.  BISILICATES  ;  II.  UXISILICATES  ; 
and  III.  SUBSILICATES. 

In  the  Bisilicates,  one  molecule  of  silicon  is  combined 
with  one  molecule  of  an  element  in  the  protoxide  state,  as 
Mg,  Ca,  Fe,  etc.,  or  one-third  of  a  molecule  of  an  element 
in  the  sesquioxide  state,  as  Al,  Fe,  Mn,  etc.;  or,  what  is 
the  same  thing,  3  molecules  of  silicon)  with  3  of  an  element 
in  the  protoxide  state,  or  1  of  an  element  in  the  sesquiox- 
ide state.  The  general  formulas  of  such  compounds  is 
hence  R03Si,  orR09Si3,  or,  if  elements  in  both  the  pro- 
toxide and  sesquioxide  state  are  present,  (R3  R)  09  Si3,  as 
explained  on  page  81. 

In  the  Unisilicates,  one  molecule  of  silicon  is  combined 
with  two  of  an  element  in  the  protoxide  state,  that  is,  for 
example,  Mg2,  Ca2,  Fe2  ;  or  with  two-thirds  of  a  molecule  in 
the  sesquioxide  state,  that  is,  two-thirds  of  =41,  Fe,  Mn. 
The  formula  of  these  silicates  is  hence  R2  04  Si,  or  Rf  04 
Si,  or,  in  order  to  remove  the  fraction  in  the  last,  R2 
Si3 ;  which  becomes,  when  elements  in  the  protoxide  and 
sesquioxide  state  are  both  present,  (R3,  R)2  0,2  Si3. 

Among  the  species  referred  to  the  Unisilicates  there  are 
some  that  vary  from  the  unisilicate  ratio.  This  occurs 
especially  in  species  in  which  an  alkali  is  present,  as  in  the 
feldspars,  micas,  and  scapolites. 

The  Subsilicates  vary  in  the  proportion  of  the  silicon  to 
the  basic  elements,  and  graduate  into  the  Unisilicates. 


BISILICATES.  243 

The  same  three  grand  divisions  exist  more  or  less  satis- 
factorily among  the  hydrous  silicates. 


A.    ANHYDROUS  SILICATES. 

I.  BISILICATES. 

The  bisilicates,  when  the  base  is  in  the  protoxide  state, 
and  hence  have  the  general  formula  R  03  Si,  are  resolved  in 
analyses  into  protoxides  and  silica  in  the  ratio  of  1RO  to 
1  Si  02,  in  which,  as  the  term  bisilieaie  implies,  the  oxygen 
of  the  silica  is  twice  that  of  the  protoxides.  If  the  base  is 
in  both  the  protoxide  and  sesquioxide  states,  giving  the  for- 
mula R3,R09Si3,  the  mineral  is  resolved  in  analyses  into 
protoxides,  sesc|iiioxidcs  and  silica.  If  the  ratio  of  the  pro- 
toxides to  sesquioxides  is  1  :  1,  the  formula  will  become 
JR3  JR  09  Si3  ;  and  analyses  give  then,  for  the  oxides  and 
silica  3  RO,  1  R  03  6  Si  0, 

Among  the  following  bisilicates  the  species  from  ensta- 
titc  to  spodumene  and  amphibole  make  a  natural  group 
called  the  hornblende,  or  hornblende  and  augite  group. 
They  are  closely  related  in  composition  and  also  in  crystal- 
lization. The  cleavage  prism  is  rhombic,  and  has  either  an 
angle  of  about  124£°  or  of  about  87°;  and  the  former  of 
these  two  rhombic  prisms  has  just  twice  the  breadth  of  the 
other  ;  that  is,  if  the  lateral  axis  from  the  front  to  the 
back  edge  in  each  be  taken  as  unity,  the  other  lateral  axis 
is  twice  as  long  in  the  prism  of  124|-°  as  it  is  in  that  of  87°. 
The  forms  are  either  trimetric,  monoclinic  or  triclinic  ; 
and  yet  the  close  relations  just  stated  exist  between  them. 
Enstatite  is  a  magnesium  or  magnesium  and  iron  species  ; 
wollastonite,  a  calcium  species  ;  rhodonite,  a  manganese 
species  ;  pyroxene  and  hornblende  contain  calcium  with 
magnesium  or  iron  ;  spodumene  contains  lithium  and  alu- 
minum, aluminum  replacing  the  elements  that  in  other 
species  are  in  the  protoxide  state. 


244  DESCRIPTIONS   OP   MINERALS. 

Enstatite. 

Trimetric.  /A  7=88°  16'.  Prismatic  cleavage  easy. 
Usually  possesses  a  fibrous  appearance  on  the  cleavage  sur- 
face. Also  massive  and  lamellar. 

Color,  grayish,  yellowish  or  greenish-white,  or  brown. 
Lustre  pearly  ;  often  metalloidal  in  the  bronzite  variety. 
H.  5-5.  G.  3-1-3-3. 

Composition.  Mg  03  Si  =  Silica  60,  magnesia  40.  B.B.  in- 
fusible, and  insoluble.  Bronzite  has  a  portion  of  the  mag- 
nesium replaced  by  iron. 

Diff.  Resembles  amphibole  and  pyroxene,  but  is  infusi- 
ble, and  trimetric  in  crystallization. 

Obs.  Occurs  in  the  Vosges  ;  Moravia ;  Bavaria ;  Baste, 
in  the  Hartz;  Leiperville  and  Texas,  Pa. ;  Brewster's,  N.  Y. 

Hypersthene  is  very  near  bronzite  in  crystalline  form  and  in  com- 
position. It  contains  a  larger  percentage  of  iron,  and  on  being  heated 
B.B.  on  charcoal  it  becomes  magnetic.  Occurs  at  St.  Paul's  Island,  in 
Labrador ;  Isle  of  Skye  ;  in  Greenland  ;  Norway,  etc. 


Wollastonite.— Tabular  Spar. 

Monoclinic.  Rarely  in  oblique  flattened  prisms.  Usually 
massive,  cleaving  easily  in  one  direction,  and  showing  a 
lined  or  indistinctly  columnar  surface,  with  a  vitreous  lustre 
inclining  to  pearly. 

Usually  white,  but  sometimes  tinged  with  yellow,  red  or 
brown.  Translucent,  or  rarely  subtransparent.  Brittle. 
H.=4-5-5.  G.  =2-75-2-9. 

Composition.  Ca  03  Si = Silica  52,  lime  48=100.  B.B. 
fuses  with  difficulty  to  a  subtransparent,  colorless  glass;  in 
powder  decomposed  by  hydrochloric  acid,  and  the  solution 
gelatinizes  on  evaporation;  often  effervesces  when  treated 
with  acid  on  account  of  the  presence  of  calcite. 

Diff.  Differs  from  asbestus  and  tremolite  in  its  more  viter- 
ous  appearance  and  fracture,  and  by  its  gelatinizing  in  acid; 
from  the  zeolites  by  the  absence  of  water,  which  all  zeolites 
give  in  a  closed  tube  ;  from  feldspar  in  the  fibrous  appear- 
ance of  a  cleavage  surface  and  the  action  of  acids. 

Obs.  Usually  found  in  granite  or  granular  limestone  ; 
occasionally  in  basalt  or  lava.  Occurs  in  Ireland  at  Dun- 
more  Head;  at  Vesuvius  and  Capo  di  Bove ;  in  the  Hartz; 
Hungary  ;  Sweden  ;  Finland  ;  Norway. 

At  Willsboro',  Lewis,  Diana,  and  Roger's  Rock,  N.  Y., 


BISILICATES. 


245 


of  a  white  color,  along  with  garnet  ;  at  Boonville,  in  bowl- 
ders with  garnet  and  pyroxene  ;  Grenville,  Lower  Canada  ; 
in  Bucks  County,  Pennsylvania  ;  at  Keweenaw  Point,  Lako 
Superior.  Edelforsite  is  impure  wollastonite. 

Pyroxene. — Augite. 

Monoclinic.    /A  7=87°  5';  cleavage  perfect  parallel  with 
the  sides  of  this  prism,  and  also  distinct  parallel  with  the 


diagonals.  Usually  in  thick  and  stout  prisms,  of  4,  6  or  8 
sides,  terminating  in  two  faces  meeting  at  an  edge.  I/\i-i 
=  133°  33',  /A  a  =  136°  27';  1  A  1  =  120°  32'.  Massive  varie- 
ties of  a  coarse  lamellar  structure  ;  also  fibrous,  fibres  often 
very  fine  and  often  long  capillary.  Also  granular,  usually 
in  coarse  granular  and  friable  masses  ;  grains  usually  angu- 
lar ;  sometimes  round  ;  also  compact  massive. 

Colors  green  of  various  shades,  verging  to  white  on  one 
side  and  brown  and  black  on  the  other,  passing  through 
Uue  shades,  but  not  yellow.  Lustre  vitreous,  inclining  to 
resinous  or  pearly  ;  the  latter  especially  in  fibrous  varieties. 
Transparent  to  opaque.  H.= 5-6.  G!=3'2-3'5. 

Composition.  It  03  Si ;  in  which  R  may  be  Ca,  Mg,  Fe, 
Mn,  and  sometimes  Zn,  K2,  Na2,  these  bases  replacing  one 
another  without  changing  the  crystalline  form,  of  which 
two  or  more  are  usually  present  ;  the  first  three  are  most 
common.  Calcium  is  always  present.  The  following  is  an 
analysis  of  a  typical  variety  :  Silica  55-0,  lime  23'5,  magne- 
sia 16'5,  manganese  protoxide  *5,  iron  protoxide  4*5  =  100. 
Fuses  B.B.,  but  its  fusibility  varies  with  the  composition, 
and  the  ferriferous  varieties  are  most  fusible.  Insoluble  in 
acids. 

Diff.  Its  crystalline  form,  and  its  ready  cleavage  in  two 
planes  nearly  at  right  angles  to  one  another,  are  the  best 
characters  for  its  determination. 

VARIETIES. — The  varieties  maybe  divided  into  three  sec- 


24:6  DESCRIPTIONS   OF  MINERALS. 

tions — the  light  colored,  the  dark  colored,  and  the  thin 
foliated. 

I.  Mdlacolite  or  white  augite  is   a  calcium  magnesium 
pyroxene,  and  includes  white  or  grayish-white  crystals  or  crys- 
talline masses.    Diopside,  of  the  same  composition,  occurs  in 
greenish- white  or  grayish-green  crystals,  and  cleavable  masses 
cleaving  with  a  bright  smooth  surface.     Sahlite  contains 
iron  in  addition,  and  is  of  a  more  dingy  green  color,  has  less 
lustre  and  coarser  structure  than  diopside,  but  is  otherwise 
similar ;   named   from  the  place   Sahla,   where  it   occurs. 
Fassaite  contains  a  little  alumina  in  addition  to  the  ele- 
ments of  sahlite,  and  is  found  in  crystals  of  rich  green  shades 
and  smooth  and  lustrous  exterior.     The  name  is  derived 
from  the  foreign  locality  Fassa.     Coccolite  is  a  general  name 
for  granular  varieties,  derived  from  the  Greek  coccos,  grain. 
The  green  is  called  green  coccolite,  the  white,  white  coccolite. 
The  specific  gravity  of  these  varieties  varies  from  3-25  to  3'3. 

Asbestus.  This  name  includes  fibrous  varieties  of  both 
pyroxene  and  hornblende  ;  it  is  more  particularly  noticed 
under  the  latter  species,  as  pyroxene  is  rarely  asbestiform. 

II.  Augite  includes  the  black  and  greenish-black  crystals, 
which  contain  a  larger  percentage  of  iron,  or  iron  and  mag- 
nesium, and  which  mostly  present  the  form  in  figure  1.     Spe- 
cific gravity  3-3-3'4.     This  is  the  common  pyroxene  of  erup- 
tive rocks.  Hedenbergite,  an  iron-calcium  pyroxene,  is  a  green- 
ish-black  opaque  variety,  in  cleavable   masses  affording  a 
greenish-brown  streak  ;  specific  gravity  3-5.   Polylite,  Hud- 
sonite,  and  Jcffersonite,  fall  here  ;  the  last  contains  some 
zinc  oxide.     These  varieties  fuse  more  easily  than  the  pre- 
ceding, and  the  globule  obtained  is  colored  black  by  the 
iron  oxide. 

III.  Diallage  is  a  thin-foliated  variety,  often  occurring 
imbedded  in  serpentine  and  some  other  rocks.     It  differs 
from  bronzite  and  hypersthene  in  crystalline  form,  and  in 
being  fusible. 

Obs.  Pyroxene  is  one  of  the  most  common  minerals.  Ifc 
occurs  in  almost  all  basic  eruptive  rocks,  like  doleryte,  as  an 
essential  constituent,  and  is  frequently  met  with  in  rocks  of 
other  kinds  ;  common  also  in  granular  limestone.  In  basalt 
the  crystals  are  generally  small  and  black  or  greenish  black. 
In  the  other  rocks,  they  occur  of  all  the  shades  of  color 
given,  and. of  all  sizes  to  a  foot  or  more  in  length.  One  crys- 
tal from  Orange  County,  measured  6  inches  in  length,  and 


I1ISILICATES.  24.7 

10  in  circumference.  White  crystals  occur  at  Canaan,  Conn*, 
Kingsbridge,  New  York  County,  and  the  Sing  Sing  quarries, 
'Westell  ester  County,  N.  Y. ;  in  Orange  County  at  several 
localities  ;  green  crystals  at  Trumbull,  Conn.,  at  various 
places  in  Orange  County,  N.  Y.,  Eoger's  Rock  and  other 
localities  in  Essex,  Lewis,  and  St.  Lawrence  counties.  Dark 
green  or  black  crystals  are  met  with  near  Edenville,  N.  Y., 
Diana,  Lewis  County.  Jeffersonite  occurs  at  Franklin,  in 
N.  J.  Green  coccolite  is  found  at  Roger's  Rock,  Long  Pond, 
and  Willsboro',  N.Y.;  black  coccolite,  in  the  forest  of  Dean, 
Orange  County,  N.  Y.  Diopside,  at  Raymond  and  Ritmford, 
lie,,  HustiYs  "farm,  Phillipstown,  N.  Y. 

Pyroxene  was  thus  named  by  Haily  from  the  Greek  pur, 
fire, 'and  xenos,  stranger,  in  allusion  to  its  occurring  in  lavas, 
where,  according  to  a  mistake  of  Hatiy,  it  did  not  belong. 
The  name  Augite  is  from  the  Greek  auge,  lustre. 

JEgerile.  Black  to  greenish  black  in  color.  It  is  a  pyroxene  con- 
taining nearly  10  per  cent,  of  soda,  and  much  iron  sesquioxide.  From 
near  Brevig  in  Norway  ;  Hot  Springs,  Arkansas. 

Acmite.  In  long  highly-polished  prisms,  of  a  dark-brown  or  reddish- 
brown  color,  with  a  pointed  extremity,  penetrating  granite,  near  Kongs- 
berg  in  Norway.  1  /\  7=86°  56',  resembles  pyroxene.  Contains  over 
12  per  cent,  of  soda.  Fuses  easily  before  the  blowpipe. 

Babingtonite.  Resembles  some  varieties  of  pyroxene .  It  occurs  in 
greenish-black  splendent  crystals  in  quartz  at  Arendal  in  Norway. 

Uralite.     Has  the  form  of  pyroxene  but  cleavage  of  hornblende. 

Rhodonite. — Manganese  Spar,  Fowlerite. 

Triclinic,  but  very  nearly  isomorphous  with  pyroxene. 
Usually  massive,  the  cleavage  often  indistinct. 

Color  reddish,  usually  deep  flesh-red  ;  also  brownish, 
greenish,  or  yellowish,  when  impure  ;  very  often  black  on 
the  surface  ;  streak  uncolored.  Lustre  vitreous.  Transpa- 
rent to  opaque.  Becomes  black  on  exposure.  H.  =5*5-6*5, 
G.=3-4-3*7. 

Composition.  Mn  03  Si  —  Silica  45*9,  manganese  protox- 
ide 54*1=100.  It  usually  contains  a  little  iron  and  lime 
replacing  the  manganese.  Becomes  dark  brown  when  heat- 
ed, and,  with  borax  in  the  outer  flame,  gives  a  deep  violet 
color  to  the  bead  while  hot,  and  a  red-brown  when  cold. 

Diff.  Resembles  somewhat  a  flesh-red  feldspar,  but  dif- 
fers in  greater  specific  gravity,  in  blackening  on  long  ex- 
posure, and  in  the  glass  with  borax. 

Obs.    Occurs  in  Sweden,  the   Hartz,  Siberia,  and  else* 


348  DESCRIPTIONS  OF   MINERALS. 

where.  In  the  United  States  it  is  found,  in  masses,  at 
Plainfield  and  Cummington,  Mass.  ;  also  abundantly  at 
Hinsdale,  and  on  Stony  Mountain,  near  Winchester,  N.  H. ; 
at  Blue  Hill  Bay,  Me.  The  black  exterior  is  a  more  or  less 
pure  hydrated  oxide  of  manganese. 

Rhodonite  may  be  used  in  making  a  violet-colored  glass, 
and  also  for  a  colored  glazing  on  stoneware.  It  receives  a 
high  polish  and  is  sometimes  employed  for  inlaid  work. 

Spodumene. 

Monoclinic.  /  A  7=87,  being  near  the  angle  of  pyroxene. 
Cleavage  easy,  parallel  to  /  and  i-i.  Surface  of  cleavage 
pearly.  Color  grayish  or  greenish.  Translucent  to  sub- 
translucent.  H.  =  6  -5-7.  G.  =  3-1-3  -19. 

Composition.  (R3,  Al)  09Si3,  in  which  R  is  lithium  and 
equals  Li2,  and  3  Li2  is  to  Al  as  1  :  4.  This  corresponds  to 
silica  64-2,  alumina  29'4,  lithia  6-4  =  100.  B.B.  becomes 
white  and  opaque,  fuses,  swells  up,  and  imparts  to  the  flame 
the  purple-red  flame  of  lithia.  Unaffected  by  acids. 

Diff.  Resembles  somewhat  feldspar  and  sea-polite,  but 
has  a  higher  specific  gravity  and  a  more  pearly  lustre,  and 
affords  rhombic  prisms  by  cleavage.  Its  lithia  reaction  is 
its  most  characteristic  test. 

Obs.  Occurs  in  granite  at  Goshen  ;  also  at  Chesterfield, 
Norwich  and  Sterling,  Mass.  ;  at  Windham,  Me.  ;  at  Brook- 
field  and  Branchville,  Ct.;  at  Uton,  in  Sweden;  Sterzing 
in  the  Tyrol ;  and  at  Killiney  Bay,  near  Dublin.  Cymato- 
lite  and  Killinite  are  results  of  its  alteration. 

This  mineral  is  remarkable  for  the  lithia  it  contains. 


Petalite. 

Monoclinic.  Usually  in  imperfectly  cleavable  masses ; 
most  prominent  cleavage  angle  141°  30'.  Color  white  or 
gray,  or  with  pale-reddish  or  greenish  shades.  Lustre  vit- 
reous to  sub-pearly.  Translucent.  H.  =  6-6'5.  G.  =  2'5. 

Composition.  Contains  lithia  like  spodumene,  and  gives 
the  percentage — Silica  77'9,  alumina  17'7,  lithia  3*1,  soda 
1-3  =  100.  Phosphoresces  when  gently  heated.  Fuses  with 
difficulty  on  the  edges.  Gives  the  reaction  of  lithia  like 
spodumene. 

Diff.  Its  lithia  reaction  allies  it  to  spodumene,  but  it 


BISILICATES.  249 

differs  from  that  mineral  in  lustre,   specific  gravity,  and 
greater  fusibility. 

Obs.  FromUto,  Sweden;  also  from  Elba  (Castor  or  Cas- 
lorite). 

Amphibole.  — Hornblende. 

Monoclinic.  /A  7=124°  30'.  Cleavage  perfect  parallel 
with  /.  Often  in  long,  slender,  flat  rhombic 
prisms  (fig.  2),  breaking  easily  transversely; 
also  often  in  6-sided  prisms,  with  oblique 
extremities.  Frequently  columnar,  with  a 
bladed  structure  ;  long  fibrous,  the  fibres 
coarse  or  fine  and  often  like  flax,  with  a 
pearly  or  silky  lustre  ;  also  lamellar ;  also 
granular,  either  coarse  or  fine. 

Colors    from    white    to    black,  passing 
through  bluish-green,  grayish-green,  green, 
and  brownish-green  shades,  to  black.^  Lus- 
tre vitreous,   with  the  cleavage  face   inclining  to  pearly. 
Nearly  transparent  to  opaque.     II.  =  5-6.     G.  =  2*9-3*4. 

Composition.  R  03  Si,  as  for  pyroxene.  11  may  corre- 
spond to  two  or  more  of  the  basic  elements  Mg,  Ca,  Fe,  Mn, 
Na2,  Kr,  the  first  three  being  most  common.  Aluminum 
is  very  often  present  in  amphibole,  replacing  a  portion 
of  the  silicon.  The  blowpipe  characters  are  like  those  of 
pyroxene.  It  fuses,  but  the  fusibility  varies  indefinitely, 
being  easiest  in  the  black  varieties. 

Diff.  It  is  distinguished  by  the  very  ready  cleavages  pa- 
rallel to  a  prism  of  124|-°,  while  pyroxene  cleaves  at  nearly 
a  right  angle  (87°  5'). 

This  species,  like  pyroxene,  has  numerous  varieties,  dif- 
fering much  in  external  appearance,  and  arising  from  the 
same  causes — isomorphism  and  crystallization. 

The  following  are  the  most  important  varieties  : 

I.      LIGHT- COLOR  ED  VARIETIES. 

TremoUtc,  Grammatite.  Tremolite  comprises  the  white 
and  grayish  crystallizations  which  usually  occur  in  blades 
or  long  crystals  penetrating  the  gangue  or  aggregated  into 
coarse  columnar  forms.  Sometimes  nearly  transparent. 
Gr.=2-9.  Formula  (Ca,  Mg)  03  Si  =  Silica  57*70,  magnesia 
28*85,  lime  J  3 '45  =  100.  The  name  is  from  the  foreign  lo- 
cality, Tremola,  in  Switzerland. 

Actinolite.    The  light-green  varieties.     It  is  a  magnesium- 


250  DESCRIPTIONS   OF   MINERALS. 

calcium-iron  ampliibole.  Glassy  actinolite  includes  the  bright 
glassy  crystals,  of  a  rich  green  color,  usually  long  and  slen- 
der, and  penetrating  the  gangue  like  tremolite.  Radiated 
actinolite  includes  olive-green  masses,  consisting  of  aggre- 
gations of  coarse  acicular  fibres,  radiating  or  divergent. 
Asbestiform  actinolite  resembles  the  radiated,  but  the  fibres 
are  more  delicate.  Massive  actinolite  consists  of  angular 
grains  instead  of  fibres.  G.  =  3'0-3  *1.  The  name  actino- 
lite alludes  to  the  radiated  structure  of  some  varieties,  and 
ij3  derived  from  the  Greek,  aktin,  a  ray  of  the  sun. 

Asbestus.  In  slender  fibres  easily  separable,  and  some- 
times like  flax.  Either  green  or  white.  Amianthus,  in- 
cludes fine  silky  varieties.  (Much  so  called  is  serpentine  ; 
serpentine  is  hydrous,  and  is  thereby  easily  distinguished.) 
Ligniform  asbestus  is  compact  and  hard  ;  it  occurs  of  brown- 
ish and  yellowish  colors,  and  looks  somewhat  like  petrified 
wood.  Mountain  leather  occurs  in  thin,  tough  sheets,  look- 
ing and  feeling  a  little  like  kid  leather  ;  it  consists  of  inter- 
laced fibres  of  abestus,  and  forms  thin  seams  between  layers 
or  in  fissures  of  rocks.  Mountain  cork  is  similar,  but  is  in 
thicker  masses ;  it  has  the  elasticity  of  cork,  and  is  usually 
white  or  grayish  white. 

The  preceding  light-colored  varieties  contain  little  or  no 
alumina  or  iron. 

Composition  of  glassy  actinolite :  Silica  59-75,  magnesia 
21*1,  lime  14 '25,  protoxide  of  iron  3!9,  protoxide  of  man- 
ganese 0*3,  hydrofluoric  acid  0*8  (Bonsdorf). 

Nephrite  is  a  very  tough  compact  variety,  related  to  tre- 
molite. Color  light-green  or  blue.  It  breaks  with  a  splin- 
tery fracture  and  glistening  lustre.  H.  — 6-6*5.  G.  =  3.  It  is 
a -magnesium-calcium  amphibole.  Nephrite  is  made  into  im- 
ages, and  was  formerly  worn  as  a  charm.  It  was  supposed  to 
be  a  cure  for  diseases  of  the  kidney,  whence  the  name,  from 
the  Greek,  nephros,  kidney.  In  New  Zealand,  China  and 
Western  America,  it  is  carved  by  the  inhabitants,  or  pol- 
lished  down  into  various  fanciful  shapes.  It  is  called  jade; 
but  the  aluminum-sodium  silicate,  called  jadeite,  is  the  stone 
most  highly  prized  of  all  those  that  are  called  jade.  Much 
of  the  mineral  from  China  called  jade  is  prehnite. 

II.      DARK-COLORED  VARIETIES. 

Cummingtonite  is  a  magnesium-iron  amphibole.  Color 
gray  or  brown  ;  usually  fibrous.  Named  from  the  locality 
where  found,  Cummington,  Mass. 


BISILICATES.  251 

•» 

Pargasite.  Dark -green  crystals,  short  and  stout  (resem- 
bling fig.  4),  with  bright  lustre,  of  which  Pargas  in  Finland 
is  a  noted  locality.  G.  =3*11. 

Composition.  Silica  45  '5,  alumina  14*9,  iron  protoxide 
8*8,  manganese  protoxide  1*5,  magnesia  14'4,  lime  14 '9= 
100. 

Hornblende.  Black  and  greenish-black  crystals  and  mas- 
sive specimens.  Often  in  slender  crystallizations  likeactino- 
lite  ;  also  short  and  stout  like  figs.  4  and  5,  the  latter  more 
especially.  It  contains  a  large  percentage  of  iron  oxide,  and 
to  this  owes  its  dark  color.  It  is  a  tough  mineral,  as  is  im- 
plied in  the  name  it  bears.  This  character,  however,  is  best 
seen  in  the  massive  specimens.  Pargasite  and  hornblende 
contain  both  alumina  and  iron. 

Composition  of  a  hornblende  :  Silica  48-8,  alumina  7*5, 
magnesia  13 '6,  lime  10  2,  iron  protoxide  18  8,  manganese 
protoxide  M^IOO. 

Obs.  Hornblende  is  an  essential  constituent  of  certain 
rocks,  as  syenyte,  dioryte  and  hornblende  schist.  Actino- 
lite  is  usually  found  in  magnesian  rocks,  as  talc,  steatite  or 
serpentine ;  tremolite  in  granular  limestone  and  dolomite  ; 
asbestus  in  the  above  rocks  and  also  in  serpentine.  Black 
crystals  of  hornblende  occur  at  Franconia,  N.  H.,  Chester, 
Mass.,  Thomastown,  Me.,  Willsboro',  N.  Y.,  in  Orange 
County,  N.  Y.,  and  elsewhere.  Pargasite  occurs  at  Phipps- 
burg  and  Parsonsfield,  Me.;  glassy  actinolite,  in  steatite 
or  talc,  at  Windham,  Readsboro',  and  New  Fane,  Vt., 
Middlefield  and  Blandforcl,  Mass.;  and  radiated  varieties 
at  the  same  localities  and  many  others.  Tremolite  and 
gray  hornblende  occiir  at  Canaan,  Ct.,  Lee,  Newburgh, 
Mass.,  in  Thomastdff  and  Raymond,  Me.,  Dover,  Kings- 
bridge,  and  in  St.  Lawrence  County,  N.  Y.  ;  at  Chestnut 
Hill,  Penn.  ;  at  the  Bare  Hills,  Md.  Asbestus  at  many  of 
the  above  localities  ;  also  Brighton  and  Sheffield,  Mass. ; 
Cotton  Rock  and  Hustis's  farm,  Phil  lips  town,  N.  Y.,  near 
the  Quarantine,  Richmond  County,  N.  Y.  Mountain  lea- 
ther is  met  with  at  Brunswick,  .N.  J.  Edenite,  a  white 
aluminous  kind,  occurs  at  Edenville,  N.  Y. 

Asbestus  is  the  only  variety  of  this  species  of  any  use  in 
the  arts.  The  flax-like  variety  is  sometimes  woven  into 
fire-proof  textures.  Its  incombustibility  and  slow  conduc- 
tion of  heat  render  it  a  complete  protection  against  the 
flames.  It  is  often  made  into  gloves.  A  fabric  whea 


252  DESCRIPTIONS   OF   MINERALS. 

dirty,  need  only  be  thrown  into  the  fire  for  a  few  minutes 
to  be  white  again.  The  ancients,  who  were  acquainted  with 
its  properties,  are  said  to  have  used  it  for  napkins,  on  ac- 
count of  the  ease  with  which  it  was  cleaned.  It  was  also 
the  wick  of  the  lamps  in  the  ancient  temples  ;  and  because 
it  maintained  a  perpetual  flame  without  being  consumed, 
they  named  it  asbestos,  unconsumed.  It  is  now  used  for 
the  same  purpose  by  the  natives  of  Greenland.  The  name 
amianthus  alludes  to  the  ease  of  cleaning  it,  and  it  is  de- 
rived from  amiantos,  undefiled.  Asbestus  is  extensively 
used  for  lining  iron  safes,  and  for  protecting  steam  pipes 
and  boilers.  The  best  locality  for  collecting  asbestus  in  the 
United  States  is  that  near  the  Quarantine,  in  Richmond 
County,  N.  Y. 

Anthophyllite  is  related  in  the  angle  of  its  prism  to  hornblende,  but 
is  trimetric.  In  composition  and  its  infusibility  before  the  blowpipe, 
it  is  near  bronzite.  B.B.  it  becomes  magnetic.  From  Kongsberg  in 
Norway,  and  near  Modum.  Kupfferite  has  the  hornblende  angle,  but 
in  composition  it  is  like  enstatite,  being  a  magnesium  silicate. 

Arfvedsonite.  Near  hornblende ;  but  contains  over  10  per  cent, 
of  soda,  like  acmite. 

Crocidolite.  Near  arfvedsonite  in  composition.  A  lavender-blue  or 
leek-green  fibrous  mineral  from  Orange  River,  South  Africa,  and  from 
the  Vosges  ;  also  from  Rhode  Island  (A.  H.  Chester). 

Gastadite.  A  dark- blue  to  azure-blue  mineral  related  to  amphibole, 
from  the  valleys  of  Aosta  and  Locano. 

Glaucophane.  A  bluish  mineral  with  the  amphibole  angle,  from  the 
Island  of  Syra.  Wichtisite  may  be  the  same  mineral. 

Milarite.  Trimetric,  of  the  composition  (KH)Cas  Al  O32  Si12  ;  the 
quantivalent  ratio  for  bases  and  silica  1:4;  being  therefore  a  quater- 
silicate  instead  of  a  bisilicate. 

Beryl. — Emeraldf^* 

Hexagonal.  In  hexagonal  prisms,  usually  without  regular 
terminations.  Cleavage  basal,  not  very  distinct. 
Rarely  massive. 

Color  green,  passing  into  blue  and  yellpw ; 
color  rather  pale,  excepting  the  deep  and  rich 
green  of  the  emerald.  Streak  uncolored.  Lus- 
tre vitreous  ;  sometimes  resinous.  Transparent 
to  subtranslucent.  Brittle.  II.  —  7*5-8.  G. — 

VARIETIES.  The  emerald  is  the  rich  green  variety  ;  it  owes 
its  color  to  the  presence  of  chromium.  Beryl  includes  the 
paler  varieties,  which  are  colored  by  oxide  of  iron.  Aqucv 


BISILICATES,  253 

marine  includes  clear  beryls  of  a  sea-green,  or  pale-bluish  01 
bluish-green  tint. 

Composition.  Be3Al  0]8Si6  =  Silica  GO'S,  alumina  19*1, 
glucina  14 '1  =  100.  Emerald  contains  less  than  one  per 
cent,  of  chromium  oxide.  B.B.  becomes  clouded,  but  does 
not  fuse  ;  at  a  very  high  temperature  the  edges  are  rounded. 
Unacted  upon  by  acids. 

Diff.  The  hardness  distinguishes  this  species  from  apa* 
tite ;  and  this  character,  and  also  the  form  of  the  crystals, 
from  green  tourmaline. 

Obs.  The  finest  emeralds  come  from  Muso,  near  Santa  Fe 
in  New  Grenada,  where  they  occur  in  dolomite.  A  crystal 
from  this  locality,  2J  inches  long  and  about  2  inches  in 
diameter,  is  in  the  cabinet  of  the  Duke  of  Devonshire  ;  it 
weighs  8  oz.  18  dwts.,  and  is  a  regular  hexagonal  prism.  A 
more  splendid  specimen,  but  weighing  only  0  oz.,  in  the 
possession  of  Mr.  Hope,  of  London,  cost  £500.  Emer- 
alds of  less  beauty,  but  of  gigantic  size,  occur  in  Siberia. 
One  specimen  in  the  royal  collection  of  Russia  measures  4J 
inches  in  length  and  12  in  breadth,  and  weighs  IGf  pounds 
troy.  Another  is  7  inches  long  and  4  broad,  and  weighs  6 
pounds.  Mount  Zalora  in  Upper  Egypt  affords  a  less  dis- 
tinct variety. 

The  finest  beryls  (aquamarines)  come  from  Siberia,  Hin- 
dostan  and  Brazil.  One  specimen  belonging  to  Dom  Pedro 
is  as  large  as  the  head  of  a  calf,  and  weighs  225  ounces,  or 
more  than  1S£  pounds  troy  ;  it  is  transparent  and  without  a 
flaw.  In  1827  a  fine  aquamarine,  weighing  35  grams,  was 
found  in  Siberia,  which  is  said  to  have  been  valued  at 
600,000  francs. 

In  the  United  States,  beryls  of  enormous  size  have  been 
obtained,  but  seldom  transparent  crystals.  They  occur  in 
granite  or  gneiss.  One  hexagonal  prism  from  Graf  ton,  N. 
H..  weighs  2,900  pounds  and  measured  4  feet  in  length,  with 
one  diameter  of  32  inches  and  another  of  22  ;  its  color  was 
bluish  green,  excepting  a  part  at  one  extremity,  which  was 
dull  green  and  yelloAV.  At  Royalston,  Mass.,  one  crystal  haa 
been  obtained  a  foot  lon<r,  and  pellucid  crystals  are  some- 
times met  with.  Haddam,  Conn.,  has  afforded  fine  crys- 
tals (see  the  figure).  Other  localities  are  Barre,  Fitchburg, 
Goshen,  Mass. ;  Albany,  Norwich,  Bowdoinham  and  Top- 
ham,  Me.;  Wilmot,  N.  H. ;  Monroe,  Portland,  Haddam, 
Conn. ;  Leiperville,  Penn. 


254:  DESCRIPTIONS   OF   MINERALS. 

Phenacite.  A  beryllium-silicate,  rhombohedral  in  crys« 
tallization.  From  the  Urals,  and  Durango  in  Mexico. 

Eudialyte.  A  pale  rose-red  mineral,  from  West  Greenland,  occurring 
in  rliombohedral  crystals,  and  containing  15 '6  per  cent,  of  zirconia. 
Eucolite  is  a  related  species  from  Norway. 

Pollucite.  An  isometric  ccesium  silicate,  white,  vitreous  in  lustre, 
with  G.=2  868.  Analysis  afforded  Rammelsberg  Silica  48  15,  alumina 
16-31,  potash  0'47,  soda  2 -48,  caesium  oxide  30  00,  water  2'59~100, 
giving  very  nearly  the  bisilicate  formula  H,CsaAl  020  Sia.  From  Elba. 


II.  UNISILICATES. 

For  the  convenience  of  the  student,  the  general  formulas 
of  the  regular  Unisilicates  are  here  re-stated.  They  are  as 
follows  : 

If  the  base  is  in  the  protoxide  state  alone,  the  formula  is 
R2  04  Si,  in  which  R  stands  for  Ca,  Mg,  Fe,  Mn,  K2,  Na2,  or 
Li2,  or  other  mutually  replaceable  base.  In  analyses,  the 
mineral  is  resolved  into  protoxides  and  silica,  in  the  ratio 
of  2  RO  to  Si02,  in  which  the  oxygen  of  the  silica  equals 
that  of  the  basic  portion. 

If  the  base  is  in  the  sesquioxide  state  alone,  the  formula 
is  R2  0J2  Si3,  in  which  R  may  stand  for  =41,  Fe,  or  Mn,  etc. 
Here  the  mineral  is  resolved,  in  analyses,  into  sesquioxides 
and  silica  in  the  ratio  of  2R03  to  3  Si  03,  in  which  the  oxy- 
gen of  the  silica  again  equals  that  of  the  basic  portion. 

If  the  basic  portion  is  partly  in  the  protoxide  state  and 
partly  in  the  sesquioxide,  the  formula,  in  its  most  general 
form,  is  (R3,  R)2  0]2  Si3.  In  this  formula  the  ratio  of  R3  to 
R  is  not  stated.  If  the  ratio  is  1  : 1,  the  formula  becomes 
R3R  0,a  Si3,  or  its  equivalent  (£R3  JR)2  012  Si,  In  a  case  like 
this  last,  the  mineral  is  resolved,  in  analyses,  into  protoxides, 
sesquioxides  and  silica,  in  the  ratio  of  3RO  :R03  :  3  Si  O2, 
in  which  again  the  oxygen  of  the  bases  equals  that  of  the 
silica* 

If  the  proportion  of  R3  to  R  is  1 :  3,  this  corresponds  to 
JR8 :  R,  or,  its  equivalent,  R :  R  ;  and  hence  the  formula  in 
its  general  form  will  be  RR  08  Si* 


TJNISILICATES. 


255 


If  the  base  is  in  the  dioxide  state,  the  formula  becomes 
K04Si,  an  example  of  which  occurs  in  zircon,  whose  for- 
mula is  Zr  04  Si. 

There  are  several  natural  groups  of  species  among  the 
Unisilicates. 


GROUP. 

1.  Chrysolite  group, 

2.  Willemite  group, 
8.  Garnet  group, 

4.  Zircon  group, 

5.  Idocrase   and  Sea- 

polite  groups, 

6.  Mica  group, 

7.  Feldspar  group, 


STATE   OF  BASES. 

protoxide, 
protoxide, 
protoxide  and) 

sesquioxide,       y 
dioxide, 
protox.   and  ses- 

quiox. 

protox.   and  ses- 
quiox . 

protox.   and   ses-  \ 
quiox.  C 


CRYSTALLIZATION. 

Trimetric. 
Hexagonal. 

Isometric. 
Dimetric. 
Dimetric. 

Tiimetric ;  plane  angle 
of  base,  120° ;  mica- 
ceous. 

Monoclinic  or  triclinic, 
/A  /nearly  120°. 


Ill  the  Scapolite,  Mica  and  Feldspar  groups  part  of  the 
species  contain  an  alkaline  metal  in  the  basic  portion,  and 
such  kinds  have  generally  an  excess  of  silica.  Among  the 
feldspars,  the  species  containing  only  calcium  as  the  protox- 
ide  base,  is  a  true  Unisjlicate.  In  the  others,  there  is  an 
excess  directly  proportional  to  the  increase  of  the  soda,  as 
explained  beyond. 

Chrysolite. — Olivine. 

Trimetric.  In  rectangular  prisms  having  cleavage  par- 
allel with  i-L  Usually  in  imbedded  grains  of  an  olive- 
green  color,  looking  like  green  bottle-glass.  Also  yellow- 
ish green.  Transparent  to  translucent.  H.:=6-7.  G.=3'3 
-3'5.  Looks  much  like  glass  in  the  fracture,  except  in  its 
having  cleavage. 

Composition.  (Mg,  Fe)904Si  =  ,  for  a  common  variety, 
Silica  41-39,  magnesia  50'90,  iron  protoxide  7'71  =  100. 
The  amount  of  iron  is  variable.  B.B.  whitens  but  is  in- 
fusible. With  borax  forms  a  yellow  bead  owing  to  the  iron 
present.  Decomposed  by  hydrochloric  acid,  and  the  solu- 
tion gelatinizes  when  evaporated.  Hyalosiderite  is  a  very 
ferruginous  variety  which  fuses  B.B. 

Diff.  Distinguished  from  green  quartz  by  its  occurring 


256 


DESCRIPTIONS   OF   MINERALS. 


disseminated  in  basaltic  rocks,  which  never  so  occurs  ;  and 
in  its  cleavage.  From  obsidian  or  volcanic  glass  it  differs 
in  its  infusibility. 

Obs.  Occurs  as  a  rock  formation ;  also  disseminated 
through  basalt  and  other  eruptive  rocks,  and  is  a  charac- 
teristic mineral  of  some  varieties  of  them.  Has  been 
found  in  New  Hampshire,  Canada,  and  elsewhere.  As  a 
rock  it  occurs  in  North  Carolina,  and  Pennsylvania.  It 
also  occurs  in  many  meteorites.  Boltonite,  from  limestone 
at  Bolton,  Mass.,  is  a  variety  of  chrysolite. 

Sometimes  used  as  a  gem,  but  it  is  too  soft  to  be  valued, 
and  is  not  delicate  in  its  shade  of  color. 

Forsterite  is  a  magnesian  chrysolite  Mga  (X  Si ;  Fayalite,  an  iron 
chrysolite,  Fe2  04  Si  ;  Monticellite,  a  calcium-magnesium,  CaMga  O4  Si ; 
Hortonolite,  an  iron-magnesium  chrysolite  from  Orange  County,  N.  Y. ; 
Rwpperite,  an  iron-manganese-zinc  chrysolite  from  Stirling  Hill,  N.  J. ; 
Tephroite,  a  manganese  chrysolite  Mn2  O4  Si,  from  Stirling  Hill,  N.  J.  ; 
Knebelite,  a  manganese- iron  chrysolite,  MnFe04Si,  from  Dannemora, 
Sweden. 

Leucoplianite  and  meliplianite  are  species  containing  the  element 
glucinum  (beryllium),  the  former  greenish  yellow  and  G=2'97,  the 
latter  yellow  and  G=3'018.  From  Norway. 

Wohlerite  contains  zirconium,  and  also  columbium  ;  color  light  yel- 
low. G=3'41. 

Willemite  is  a  zinc  unisilicate,  Zn204  Si.     See  page  157. 

Dioptase  is  a  copper  silicate,  which,  making  the  water  basic,  is  a 
uniailicate,  H2CuO4Si.  See  page  141. 

Friedelite  is  a  rose-red  manganese  silicate  of  the  general  formula 
R2  04  Si,  in  which  R  consists  of  manganese  and  hydrogen  in  the  atomic 
ratio  2 : 1. 

IMmte  (Helvin).  Isometric  ;  in  tetrahedral  crystals.  Color  honey- 
yellow,  brownish,  greenish.  Lustre  vitreo  -  resinous.  H.—  6-6 '5. 
G.  =3'1  3'3.  Contains  manganese,  iron,  and  glucinum,  and  some 
sulphur.  From  Saxony,  and  Norway. 

Danaiite.  Isometric  ;  in  octahedral  crystals.  Color  flesh-red  to 
gray.  Lustre  vitreo-resinous.  H.  =5-5.  G.  =3 '427.  Contains  zinc, 
glucinum,  iron,  manganese.  Found  disseminated  through  the  granite 
at  Rockport,  Cape  Ann,  Mass.,  and  also  near  Gloucester,  Mass. 

Eulytite  is  a  bismuth  silicate,  and  Bismutoferrite  a  bismuth-and- 
iron silicate. 

Garnet. 

Isometric.  Common  in  dodecahedrons  (fig.  1),  also  in 
trapezohedroris  (fig.  2),  and  both  forms  are  sometimes  vari- 
ously modified.  Cleavage  parallel  to  the  faces  of  the  dode- 
cahedron ;  sometimes  rather  distinct.  Also  found  massive 
granular,  and  coarse  lamellar. 


UNISILICATES.  257 

Color  deep  red  to  cinnamon  color ;  also  brown,  black, 
green,  emerald-green,  white.  Transparent  to  opaque.  Lus- 
tre vitreous.  Brittle.  H.  =6-5-7*5.  G.  =3-1-4-3. 


Composition  and  Varieties.  The  general  formula  for  the 
species  is  (R3Kr)2  0,2Si3;  in  which  1?  may  be  calcium,  mag- 
nesium, iron,  manganese,  and  R  may  be  aluminum,  iron, 
chromium.  The  varieties  owe  their  differences  to  the  pro- 
portions of  these  elements,  or  the  substitution  of  one  for 
another.  Most  garnets  fuse  easily  to  a  brown  or  black  glass  ; 
but  the  fusibility  varies  with  the  constituents,  and  chrome- 
garnet  is  infusible.  They  are  not  decomposed  by  hydro- 
chloric acid  ;  but  if  first  ignited,  then  pulverized  and  treated 
with  acid,  they  are  decomposed,  and  the  solution  usually 
gelatinizes  when  evaporated. 

There  are  three  series  among  the  varieties  :  one,  that  of 
alumina-garnet,  in  which  the  sesquioxide  base  is  chiefly 
aluminum  ;  the  second,  that  of  iron-garnet,  in  which  the 
sesquioxide  base  is  chiefly  iron  instead  of  aluminum  ;  and 
third,  chrome-garnefc,  in  which  it  is  chromium. 

I.  ALUMINA-GARNET. 

Almandite  (Almandine).  An  iron  alumina-garnet,  Fe3 
Al  Oi2Si3= Silica  36*1,  alumina  20'6,  iron  protoxide  43*3  = 
100.  It  occurs  of  various  shades  of  red  from  ruby-red  and 
hyacinth-red,  to  columbine-red  and  brownish  red.  When 
transparent  it  is  called  precious  garnet  ;  and,  if  not  so, 
common  garnet. 

Grossularite  (including  Cinnamon  Stone}.  A  lime  alu- 
mina-garnet, Ca3Al  012Si3= Silica  40*1,  alumina  22*7,  lime 
37-2  =  100,  but  often  with  some  iron  protoxide  in  place  of 
part  of  the  lime.  The  name  Grossularite  was  given  to  a 
pale-green  garnet,  in  allusion  to  the  color,  from  the  Latin 
name  for  gooseberry.  Cinnamon  Stone  includes  the  cinna- 
mon-colored variety. 


258  DESCRIPTIONS   OP   MINERALS. 

Pyrope.  A  magnesia  alumina-garnet  Mg3Al  012Si3.  Color 
deep  red,  but  varying  to  black  and  green. 

Spessartite.  A  manganese  alumina-garnet  (Mn,Fe)3Al 
O,2  Sit,  some  iron  replacing  part  of  the  manganese.  Color 
red,  brownish  red,  hyacinth-red.  A  Haddam  specimen  af- 
forded Seybert,  Silica  35 '8,  alumina,  18-1,  iron  protoxide 
14*9,  manganese  protoxide  31*0. 

II.  IRON-GARNET. 

Andradite.  A  lime  iron-garnet,  Ca3Fe012Si3.  Colors 
various,  from  that  of  almandite  or  common  garnet,  to  a 
wine-yellow,  as  in  Topazolite ;  green,  as  in  Jelletite ;  and 
black,  as  in  Melanite  and  Pyreneite. 

ColopJwnite  is  a  dark-red  to  brownish-yellow  coarse  gran- 
ular garnet  having  often  iridescent  hues. 

Aplome  is  a  red  variety.  Rothoffite  has  manganese  in  place 
of  part  of  the  lime,  and  a  yellowish-brown  to  reddish-brown 
color. 

Ytter-garnet  contains  yttria  in  place  of  part  of  the  lime. 

Bredbergite.     A  lime-magnesia  iron-garnet. 

III.  CHROME-GARNET. 

Ouvarovite.  An  emerald-green  lime  chrome-garnet  (Ca, 
Mg)3Ee012Si3.  G.  =  3-41-3-42. 

Diff,  The  vitreous  lustre  of  fractured  garnet,  and  its 
usual  dodecahedral  forms,  are  easy  characters  for  distin- 
guishing it. 

Obs.  Garnet  occurs  abundantly  in  mica  schist,  horn- 
blende schist,  and  gneiss,  and  somewhat  less  frequently  in 
granite  and  granular  limestone  ;  sometimes  in  serpentine; 
occasionally  in  trap,  and  other  igneous  rocks. 

The  best  precious  garnets  are  from  Ceylon  and  Green- 
land ;  cinnamon  stone  comes  from  Ceylon  and  Sweden  ; 
grossularite  occurs  in  the  AVilui  River,  Siberia,  and  at  Tel- 
lemarken  in  Norway ;  green  garnets  are  found  at  Schwartz- 
enberg,  Saxony  ;  melanite,  in  the  Vesuvian  lavas  ;  ouvaro- 
vite^at  Bissersk  in  Russia;  topazolite,  at  Mussa,  Piedmont. 

In  the  United  States,  precious  garnets,  of  small  size,  oc- 
cur at  Hanover,  N".  H. ;  and  a  clear  and  deep  red  variety, 
sometimes  called  pi/rope,  comes  from  Green's  Creek,  Dela- 
ware County,  Penn.  Dodecahedrons,  of  a  dark  red  color, 
occur  at  Haverhill  and  Springfield,  N,  H.,  some  1£  inches 
through;  also  at  New  Fane,  Vt.,  still  larger;  at  Unity, 
Brunswick,  Streaked  Mountain,  and  elsewhere,  Maine  ;  at 
Monroe,  Lyme  and  Redding,  Conn. ;  Bedford,  Chesterfield, 


UNISILICATES. 


259 


Barre,  Brookfield,  and  Brimfield,  Mass. ;  Dover,  Dutchess 
County.  Roger's  Rock,  Crown  Point,  Essex  County,  N.  Y. ; 
Franklin,  N.  J.  Cinnamon-colored  crystals  occur  at  Carlisle, 
Mass.,  transparent,  and  also  at  Boxborough  ;  with  ido- 
crase  at  Parsonstield,  Phippsburg  and  Rumford,  Me.  ;  afc 
Amherst,  N.  H. ;  at  .Amity,  K.  Y.,  and  Franklin,  N.  J. ; 
at  Dixon's  Quarry,  seven  miles  from  Wilmington,  Del.,  in 
fine  trapezohedral  crystals.  Melanite  is  found  at  Franklin, 
N.  J.,  and  German  town,  Perm.  Chrome  garnet  is  found 
in  Orford,  Canada.  Oolophonite  is  abundant  at  Willsbor- 
ough  and  Lewis,  Essex  County,  H.  Y. :  it  occurs  also  at 
North  Madison,  Conn. 

The  garnet  is  the  carbuncle  of  the  ancients.  The  ala- 
bandic  carbuncles  of  Pliny  were  so  called  because  cut  and 
polished  at  Alabanda,  and  hence  the  name  Almandine  now 
in  use.  The  garnet  is  also  supposed  to  have  been  the  hya- 
cinth of  the  ancients. 

The  clear  deep-red  garnets  make  a  rich  gem,  and  are 
much  used.  Those  of  Pegu  are  most  highly  valued.  They 
are  cut  quite  thin,  on  account  of  their  depth  of  color.  The 
cinnamon  stone  is  also  employed  for  the  same  purpose. 
Pulverized  garnet  is  sometimes  employed  as  a  substitute 
for  emery. 

Pliny  describes  vessels,  of  the  capacity  of  a  pint,  formed 
from  large  carbuncles,  "devoid  of  lustre  and  transpa- 
rency, and  of  a  dingy  color/'  which  probably  were  large 
garnets. 

Zircon. 

Dimetric.  /A/=132°10';  1M  =  123°19'.  Cleavage  parallel 
to  /,  but  imperfect.  Usually  in  crystals  ;  but  also  granular. 

1. 


Color  brownish  red,  brown,  and  red,  of  clear  tints  ;  also 
yellow,  gray,  and  white.  Streak  uncolored.  Lustre  more 
or  less  adamantine.  Often  transparent ;  also  nearly  opaque. 
Fracture  conchoidal,  brilliant.  H.  =  7'5.  G.  —  4-0-4*8. 


•360  DESCRIPTIONS   OP  MINERALS. 

Composition.  Zr  O4 Si  =  Silica  33,  zirconia  67=100.  B.B. 
infusible,  but  loses  color. 

VARIETIES.  Transparent  red  specimens  are  called  hya- 
cinth. A  colorless  variety  from  Ceylon,  having  a  smoky 
tinge,  is  called  jargon;  it  is  sold  for  inferior  diamonds, 
which  it  resembles,  though  much  less  hard.  The  name 
zirconite  is  sometimes  applied  to  crystals  of  gray  or  brown- 
ish tints. 

Diff.  Zircon  is  readily  distinguished  from  species  which 
it  resembles  in  other  properties  by  its  square  prismatic 
form,  specific  gravity,  and  adamantine  lustre. 

Obs.  The  zircon  is  confined  to  crystalline  rocks,  occurring 
in  granite,  gneiss,  granular  limestone,  and  some  igneous 
rocks.  Zircon-syenyte  is  a  syenyte  with  disseminated  zircons. 
Zircon  often  occurs  in  auriferous  sands.  Hyacinth  occurs 
mosth  in  grains  in  such  sands,  and  comes  from  Ceylon, 
Auvergne,  Bohemia,  and  elsewhere  in  Europe.  Siberia 
affords  crystals  as  large  as  walnuts.  Splendid  specimens 
come  from  Greenland. 

In  the  United  States,  fine  crystals  of  zircon  occur  in  Bun- 
combe County,  N.  C.  ;  of  a  cinnamon-red  color  in  Moriah, 
Essex  County,  N.  Y.  ;  also  at  Two  Ponds  and  elsewhere, 
Orange  County,  in  crystals  sometimes  an  inch  and  a  half 
long ;  in  Hammond,  St.  Lawrence  County,  and  Johnsbury, 
Warren  County,  N.  Y. ;  at  Franklin.  N.  J.  ;  in  Litchfield, 
Me.  ;  Middlebury,  Vt.  ;  in  Canada,  at  Grenville,  etc. 

The  name  hyacinth  is  from  the  Greek  huakinthos.  But 
it  is  doubtful  whether  it  was  applied  by  the  ancients  to 
stones  of  the  zircon  species. 

The  clear  crystals  (hyacinths)  are  of  common  use  in 
jewelry.  When  heated  in  a  crucible  with  lime,  they  lose 
their  color,  and  resemble  a  pale  straw-yelloAV  diamond,  for 
which  they  are  substituted.  Zircon  is  also  used  in  jeweling 
watches.  The  hyacinth  of  commerce  is  to  a  great  extent 
cinnamon  stone,  a  variety  of  garnet.  The  earth  zirconia 
is  used  as  an  advantageous  substitute  for  lime  in  the  oxyhy- 
drogen  lantern. 

Auerbachite,  Malacon,  Tachyaphcdtite,  CErstedite,  Bragite,  are 
names  of  zircon-like  minerals  supposed  to  be  zircon  partly  altered. 

The  earth  zirconia  is  also  found  in  the  rare  minerals  eudialyte  and 
wohlerite ;  also  in  polymignite,   ceschynite;  also  sparingly  in 
wnite. 


UNISILICATES. 


261 


Vesuvianite. — Idocrase. 

Dimetric.  0  :  1  =  142°  46' ;  1  Al=129°  21',  1  :  ^'=127° 
14'.  Cleavage  not  very  distinct  parallel  with  /.  Also  found 
massive  granular,  and  subcolumnar. 


4. 


Color  brown  ;  sometimes  passing  into  green.  In  some 
varieties  the  color  is  oil-green  in  the  direction  of  the  axis 
and  yellowish  green  at  right  angles  with  it.  Streak  un- 
colored.  Lustre  vitreous.  Subtransparent  to  nearly  opaque. 
H.  =  6-o.  G.=3-33-3-4. 

Composition.  (fCa3-fAl)2012  Si3.  A  small  part  of  the 
Ca  is  usually  replaced  by  magnesium,  and  part  of  the  alu- 
minum sometimes  by  iron  in  the  sesquioxide  state.  Per- 
centage of  a  common  variety,  Silica  37'3,  alumina  16'1, 
iron  sesquioxide  3-7,  lime  35 -4,  magnesia  2-1,  iron  protox- 
ide 2*9,  water  2*1  =  99 '6.  B.B.  fuses  easily  with  efferves- 
cence to  a  greenish  or  brownish  globule. 

Diff.  Resembles  some  brown  varieties  of  garnet,  tourma- 
line and  epidote,  but  besides  its  difference  of  crystallization, 
it  is  much  more  fusible. 

Obs.  Vesuvianite  was  first  found  in  the  lavas  of  Vesuvius, 
and  hence  the  name.  It  has  since  been  obtained  in  Pied- 
mont ;  near  Christiania,  Norway  ;  in  Siberia ;  also  in  the 
Fassa  Valley.  Cyprine  includes  blue  crystals  from  Telle- 
marken,  Norway  ;  supposed  to  be  colored  by  copper. 

In  the  United  States,  it  occurs  in  fine  crystals  at 
Phippsburg  and  Rumford,  Sandford,  Parsonsfield  and 
Poland,  Me.  ;  Newton,  N.  J.;  Amity,  N.  Y.  In  Canada  at 
Calumet  Falls,  and  at  Grenville. 

The  name  idocrase  is  from  the  Greek  eido,  to  see,  and 
krasis,  mixture  ;  because  its  crystalline  forms  have  much 
resemblance  to  those  of  other  species. 

This  mineral  is  sometimes  cut  as  a  gem  for  rings. 

MellUite  in  honey-yellow  crystals  (which  includes  Hum- 


DESCRIPTIONS   OF  MINERALS. 

"boldtilite)  is  a  related  dimetric  species,  from  Capo  di  Bove, 
near  Eome,  and  Mount  Somma,  Vesuvius, 

Epidote. 

Monoclinic.  i-iM  t  =  115°24'.  t-i'A  — l-i  =  116°  18'.  — lA 
-1  =  109°  35'.  Cleavage  parallel  to 
i-i ;  less  distinct  parallel  to  1-i. 
Also  massive  granular  and  forming 
rock  masses  ;  sometimes  columnar 
or  fibrous. 

Color  yellowish  green  (pistachio- 
green)  and  ash-gray  or  hair-brown.  Streak  uncolored. 
Translucent  to  opaque.  Lustre  vitreous,  a  little  pearly 
on  i-i ;  often  brilliant  on  the  faces  of  crystals.  Brittle.  H. 
=  6-7.  G.  =  3'25-3'5. 

Composition.  A  lime  iron-alumina  silicate,  the  iron  being 
mostly  in  the  sesquioxide  state  and  replacing  aluminum. 
Percentage  of  common  variety,  Silica  37 '83,  alumina  22-63, 
iron  sesquioxide  15-02,  iron  protoxide  0'93,  lime  23*27, 
water  2 -05  =100 -73. 

B.B.  epidote  fuses  with  effervescence  to  a  black  glass 
which  usually  is  magnetic.  Partially  decomposed  by  hy- 
drochloric acid,  but  if  first  ignited,  is  then  decomposed, 
and  the  solution  gelatinizes  on  evaporation. 

Green  epidote  is  often  called  Pistacite.  Piedmontite  is 
a  variety  containing  much  manganese,  of  reddish -brown  or 
reddish-black  color. 

Bucklandite  is  an  iron-epidote. 

Diff.  The  peculiar  yellowish-green  color  of  ordinary  epi- 
dote distinguishes  it  at  once.  From  zoisite  and  vesuvian- 
ite  it  differs  in  fusing  to  a  black  magnetic  globule. 

Obs.  Occurs  in  crystalline  rocks,  especially  in  hornblen- 
dic  rocks.  It  often  occurs  in  the  cavities  of  amygdaloidal 
rocks.  Splendid  crystals,  six  inches  long,  and  with  bril- 
liant faces  and  rich  color,  have  been  obtained  at  Haddam, 
Ct.  Crystallized  specimens  are  also  found  at  Franconia, 
N.  H./Hadlyme,  Chester,  Newbury  and  Athol,  Mass.; 
near  TJnity,  Amity,  and  Monroe,  $T.  Y. ;  Franklin  and 
Warwick,  N.  J. ;  Pennsylvania,  at  E.  Bradford  ;  Michigan, 
in  the  Lake  Superior  region  ;  Canada,  at  St.  Joseph. 

The  name  epidote  was  derived  by  Haiiy  from  the  Greek 
epidiclomi,  to  increase,  in  allusion  to  the  fact  that  the  base 
of  the  primary  is  frequently  mu^h  enlarged  in  the  crystals. 


UNISILICATES.  263 

Zoisite.  A  mineral  of  the  epidote  group,  occurring  in  trimetric  crys- 
tals, with  /A/=H6°  40',  and  having-  a  white,  pale-grayish,  pale- 
greenish  to  reddish  color  ;  also  massive.  H.  =6-6*5.  G.  =3*1-3*4. 

It  is  a  lime-epidote,  with  little  or  no  iron.  B.B.  swells  up  and 
fuses  to  a  white  blebby  glass  ;  after  ignition,  gelatinizes  with  hydro- 
chloric acid.  Thulite  is  a  rose-red  variety.  Occurs  at  Saualpe  in  Carin- 
thia,  in  the  Tyrol ;  Arendal,  etc. ;  in  Vermont  at  Willsboro'  and  Mont- 
pelier  ;  in  Massachusetts,  at  Goshen,  Chesterfield,  etc. ;  in  Pennsyl- 
vania at  Unionville,  and  in  Tennessee  at  the  Ducktown  copper  mine. 

Saussurite,  from  the  euphotide  of  the  Alps  in  the  vicinity  of  Lake 
Geneva,  approaches  zoisite  in  composition,  it  affording  Hunt  Silica 
43*59,  alumina  27 '72,  iron  sequioxide  2'61,  magnesia  2*98,  lime  19'71, 
water  0-35,  soda  3'08  =  100'04.  Color  whitish,  greenish  gray,  ash-gray  ; 
G.  =3  226-3*385.  H.=6'5-7.  The  saussurite  of  Orezza  gave  nearly  the 
same  composition  in  an  analysis  by  Boulanger,  and  that  of  Schwartz- 
wald  in  general  the  same,  with  more  of  magnesia  and  less  of  lime,  in 
an  analysis  by  Hutlin.  The  high  specific  gravity  separates  it  from 
scapolite  (wernerite)  which  it  resembles  in  composition,  and  also  from 
the  feldspar  group. 

Jadeite,  one  of  the  kinds  of  pale-green  stones  used  in  China  for 
ornaments,  called  feitsui,  has  the  high  specific  gravity  of  zoisite,  but 
it  has  nearly  the  composition  of  oligoclase,  if  the  iron  and  magnesia 
be  excluded;  analysis  by  Damour  affording  "Silica  59 '17.  alumina 
22-58,  iron  protoxide  1  "56,  magnesia  115,  lime  2 '68,  soda  12  *93  =  100  "07. 
It  is  the  material  of  some  of  the  ornaments  in  the  Swiss  lake-dwell- 
ings. 

Allanite. — A  cerium  epidote,  of  a  pinchbeck-brown  to  brownish- 
black  and  black  color,  submetallic  to  pitch-like  and  resinous  in  lustre, 
crystallizing  in  the  monoclinic  system,  and  with  the  angles  nearly  of 
epidote.  H.  =5*5-6.  G.  =3-4*2. 

B.B.  fuses  easily  and  swells  up  to  a  dark,  blebby  magnetic  glass. 
Most  varieties  gelatinize  with  hydrochloric  acid,  but  not  after  igni- 
tion. Found  in  Norway,  Sweden,  Greenland,  Scotland  ;  at  Snarum, 
near  Dresden  ;  in  Massachusetts,  at  the  Bolton  quarry  ;  in  New  York, 
at  Moriah  in  Essex  County,  Monroe  in  Orange  County  ;  in  New  Jersey, 
at  Franklin;  in  Pennsylvania,  at  East  Bradford  and  Eaton  ^  in  Vir- 
ginia, Amherst  County  ;  in  Canada,  at  St.  Paul's. 

Orthite  is  a  variety  in  long  slender  crystals.  Muromontite,  Bodcnite, 
and  Michaelsonite  are  related  minerals. 

Gadolinite.  A  mineral  of  a  greenish-black  color,  containing  lithium, 
cerium,  and  barium,  from  Sweden,  Greenland,  and  Norway.  Crystals 
monoclinic,  with  1 A /=  116°.  H.=6*5-7.  G.=4-4'5. 

Mosandrite.  Reddish-brown  to  dull  greenish  or  yellowish-brown 
silicate  of  cerium,  lanthanum  and  didymium,  calcium,  and  titanium. 
H.=4.  G. =2*9-3-03.  From  Brevig,  Norway. 

llvaite  ( Yenite).  In  trimetric  striated  prisms,  of  an  iron-black  to 
grayish-black  color.  /A/=112°  38'.  H.=5'5-6.  G.=3  7-4'2.  In 
composition  a  calcium-iron  silicate  in  which  part  of  the  iron  h  in 
the  sesquioxide  state.  From  Elba;  Fossum  and  Skeen  in  NOT  ^ay, 
etc.  Also  reported  as  occurring  at  Cumberland,  R.  I.,  and  Milk  /tow 
quarry,  in  Somerville,  Mass.  The  name  Ifaaite  is  derived  frotp  the 
Latin  name  of  the  Island  of  Elba, 


264 


DESCRIPTIONS   OF   MINERALS. 


Axinite. 


Triclinic.      In  acute-edged   oblique  rhomboidal  prisms  ; 
°      '  °      '  =°      ' 


45' 


38',  PAw=135°  31'.     Cleavage 
indistinct.  Also  rarely  massive  or  lamellar. 

Color  clove-brown  ;  differing  some- 
what in  shade  in  three  directions,  being 
trichroic.  Lustre  vitreous.  Transpa- 
rent to  subtranslucent.  Brittle.  H.  = 
6-5-7.  G.=3'27.  Pyro-electric. 

Composition.  A  unisilicate,  afford- 
ing boron  trioxide,  and  containing 
boron  among  its  bases.  One  analysis 
afforded  Silica  43-68,  boron  trioxide 
5-61,  alumina  15-63,  iron  sesquioxide 
9-45,  manganese  sesquioxide  3-05,  lime 
20-92,  magnesia  T70,  potash  0-64= 
100-43.  B.B.  fuses  easily  with  intum- 
escence to  a  dark-green  or  black  glass, 
imparting  a  pale-green  color  to  the 
flame,  which  is  due  to  the  boron. 

Diff.  Remarkable  for  the  sharp  thin  edges  of  its  crystals, 
and  its  glassy  brilliant  appearance,  without  cleavage.  The 
crystals  are  implanted,  and  not  disseminated  like  garnet.  In 
one  or  all  of  these  particulars,  and  also  in  blowpipe  reaction, 
it  differs  from  any  of  the  titanium  ores. 

Obs.  Occurs  at  St.  Cristophe  in  Dauphiny  ;  at  Kongs- 
berg  in  Norway  ;  Normark  in  Sweden  ;  Santa  Maria,  in 
Switzerland  ;  Cornwall,  England  ;  Thum  in  Saxony,  whence 
the  name  T  hummer  stein  and  Thumite. 

In  the  United  States  it  has  been  found  at  Phippsburg  and 
"Wales  in  Maine  ;  and  at  Cold  Spring,  New  York. 

Dariburite.  A  silicate  which  contains,  like  axinite,  boron  trioxide. 
Composition:  Silica  48  '8,  boron  trioxide  28-5,  lime  22'7.  Occurs  with 
oligoclase  and  orthoclase  in  imbedded  masses  of  a  pale-yellow  color, 
at  Danbiiry,  Conn.  H.=7.  G.=2-95-2'96. 


lolite. — Dichroite.     Cordierite. 

Trimetric.  In  rhombic  prisms  of  120°,  and  in  6  and  12- 
sided  prisms.  Also  massive.  Cleavage  indistinct ;  but  crys- 
tals often  separable  into  layers  parallel  to  the  base,  especially 
after  partial  alteration. 

Color  various  shades  of  blue,  looking  often  like  a  pale  or 


MICA   GROUP.  265 

dark  blue  glass  ;  often  deep  blue  in  direction  of  the  axis,  and 
yellowish  gray  transversely.  Streak  uncolored.  Lustre  vit- 
reous. Transparent  to  translucent.  Brittle.  H.  =7-7'5. 
G.  =2-6-2-7. 

Composition.  A  silicate  of  aluminum,  magnesium  and 
iron,  corresponding  to  Silica  49*4,  alumina  33*9,  magnesia 
8-8,  iron  protoxide  7-9  =  100.  B.B.  loses  its  transparency 
and  with  much  difficulty  fuses. 

Diff.  The  glassy  appearance  of  iolite  is  so  peculiar  that  it 
can  be  confounded  with  nothing  but  blue  quartz,  from  which 
it  is  distinguished  by  its  fusing  on  the  edges.  It  is  easily 
scratched  by  sapphire. 

Obs.  Found  atHaddam,  Conn.,  in  granite  ;  also  in  gneiss 
at  Brimfield,  Mass.;  at  Richmond,  N.  H.,  in  talcose  rock. 
The  principal  foreign  localities  are  at  Bodenmais  in  Bavaria; 
Arendal,  Norway ;  Capo  de  Gata,  Spain ;  Tunaberg,  Fin- 
land ;  also  Norway,  Greenland  and  Ceylon. 

The  name  iolite  is  from  the  Greek  ion,  violet,  alluding 
to  its  color  ;  it  is  also  called  dichroite,  from  dis,  twice,  and 
chroa,  color,  owing  to  its  having  different  colors  in  two  di- 
rections. 

Occasionally  employed  as  an  ornamental  stone,  and  is  cut 
so  as  to  present  different  shades  of  color  in  different  direc- 
tions. 

Iolite  exposed  to  the  air  and  moisture  undergoes  a  gradual  altera- 
tion, becoming  hydrous,  and  assuming  a  foliated  micaceous  structure, 
so  as  to  resemble  talc,  though  more  brittle  and  hardly  greasy  in  feel. 
Hydrous  Iolite,  FaMunite,  Chlorophyllite,  and  EsmarJdte,  are  names 
that  have  been  given  to  the  altered  iolite  ;  and  Gigantolite  and  a  num- 
ber of  other  like  minerals  are  of  the  same  origin.  (See  p.  315.) 


MICA  GROUP. 

The  minerals  of  the  mica  group  are  alike  in  having 
(1)  their  crystals  monoclinic ;  (2)  the  front  plane  angle  of 
the  base,  or  of  the  cleavage  laminae,  120°;  (3)  cleavage  emi- 
nent, parallel  to  the  base,  affording  very  thin  laminae  ;  and 
(4)  aluminum  and  potassium  among  the  essential  constituents. 
The  combining  or  quantivalent  ratio  for  the  bases  and  sili- 
con is  usually  1  to  1  in  Biotite,  Phlogopite,  and  Lepidome- 
lane ;  1  to  more  than  1  in  Muscovite,  Lepidolite,  etc. 


266  DESCRIPTIONS   OF   MINERALS. 

The  ordinary  light-colored  micas  are  mostly  Muscovite,  and 
the  black,  mostly  Biotite.  Lepidolite  is  a  light-colored  mica 
containing  lithia ;  and  Lepidomelane  a  black  mica  containing 
more  iron  than  biotite.  Muscovite  and  biotite  are  so  closely 
related  that  crystals  of  the  latter  often  occur  that  are  fin- 
ished out  uninterruptedly  by  muscovite,  the  axial  lines  of  the 
one  continuous  with  those  of  the  other;  and  such  crystals 
are  sometimes  several  inches  across.  There  is  here  a  com- 
pound structure  chemically,  but  no  twinning  in  the  crystal- 
lization. When  a  thin  plate  of  mica  is  struck  with  a  pointed 
awl  or  other  tool  a  symmetrical  star  of  six  rays  is  produced, 
the  rays  being  cleavage  lines  parallel  to  the  sides  of  the 
rhombic  prism  /  and  the  shorter  diagonal. 

Biotite. 

Monoclinic.  Crystals  usually  short  erect  rhombic  or  hex- 
agonal prisms.  Common  in  disseminated  scales ;  also  in 
masses  made  up  of  an  aggregation  of  scales. 

Color  dark  green  to  black,  rarely  white.  Transparent  to 
opaque.  Lustre  more  or  less  pearly  on  a  cleavage  surface. 
Optic-axial  angle  usually  less  than  1°  ;  crystals  appear  often 
to  beuniaxial.  H.  =2-5-3.  G.  =2-7-3-1. 

Composition.  Mostly  (K2,Mg,Fe)3  Al  0]2Si6,  a  variety  af- 
forded Silica  40-91,  alumina  17 '79,  iron  oxides  10-00,  mag- 
nesia 19-04,  potash  9-96.  B.B.  whitens  and  fuses  on  thin 
edges  ;  sometimes  the  flame  is  red  owing  to  the  presence  of 
a  little  lithium. 

Lepidomelane.  Like  biotite,  but  containing  more  iron  oxides  and 
less  of  magnesia  than  biotite,  and  folia  brittle.  Puses  easily  to  a 
black  magnetic  globule.  Annite  (from  Cape  Ann,  Mass.)  is  near  Lepi- 
domelane. 

Phlogopite.  Contains  much  magnesia  and  little  or  no  iron.  Color 
yellowish  brown  to  brownish  red,  somewhat  copper-like  in  its  reflec- 
tions  ;  also  white  or  colorless.  Optic-axial  angle  3°  to  20'.  H.=2  5-3. 
G.=r2'78-2-85.  In  crystals  and  scales  in  granular  limestone  Prom 
Gouverneur,  Edwards,  and  other  places  in  Northern  New  York  ;  Stir- 
ling Mine,  and  Newton,  N.  J. ;  St.  Jerome,  and  Burgess,  Canada  ;  in 
the  Vosges.  Aspidolite,  from  the  Tyrol,  is  a  related  mica. 

Astrophyllite.  A  bronze-yellow  mica  affording  nearly  8  per  cent,  of 
titanium  dioxide.  From  Brerig,  Norway,  and  El  Paso  County,  Colo- 
rado. 


MICA    GROUP.  267 

Muscovite. — Common  Mica. 

Monoclinic.  In  oblique  rhombic   prisms   of  about  120°. 
Crystals  commonly  have  the  acute  edge  replaced,  as  in  the 
accompanying  figure  (plane  i-i).     Usu- 
ally in  plates  or  scales.     Sometimes  in 
radiated  groups  of  aggregated  scales  or 
small  folia. 

Colors  from  white  through  green, 
yellowish  and  brownish  shades  ;  rarely 
rose-red.  Lustre  more  or  less  pearly. 
Transparent  or  translucent.  Tough 
and  elastic.  H.=2-2-5.  G.=2'7-3. 
Optic-axial  angle  44°  to  78°. 

Composition.  A  common  variety  afforded  Silica  46-3, 
alumina  36-8,  potash  9-2,  iron  sesquioxide  4-5,  fluoric  acid 
0*7,  water  1*8— 99*3.  Often  contains  3  to  5  per  cent,  of 
water,  and  thus  passes  to  a  hydrous  mica  called  Margaro- 
dite.  (See  page  313).  B.B.  whitens  and  fuses  on  the  thin- 
nest edges,  but  with  great  difficulty,  to  a  gray  or  yellow 
glass. 

A  variety  in  which  the  scales  are  arranged  in  a  plu- 
mose form  is  called  plumose  mica ;  another,  in  which  the 
plates  have  a  transverse  cleavage,  has  been  termed. prismatic 
mica. 

Diff.  Differs  from  talc  and  gypsum  in  affording  thinner 
and  much  tougher  folia,  and  in  being  elastic  ;  but  musco- 
vite  when  hydrous  loses  its  elasticity,  and  becomes  more 
pearly  in  lustre. 

Obs.  Muscovite  is  a  constituent  of  granite,  gneiss  and  mica 
schist,  and  gives  to  the  latter  its  schistose  structure.  It  also 
occurs  in  granular  limestone.  Plates  two  and  three  feet  in 
diameter,  and  perfectly  transparent,  have  been  obtained  at 
Alstead,  and  Grafton,  New  Hampshire,  and  it  has  been 
mined  at  these  places,  and  in  Orange  and  elsewhere.  Other 
good  localities  are  Paris,  Me. ;  Chesterfield,  Barre,  Brimfield, 
and  South  Royalston,  Mass. ;  near  Greenwood  Furnace,  War- 
wick and  Edenville,  Orange  County,  and  in  Jefferson  and 
St.  Lawrence  counties,  N.  Y . ;  Newton  and  Franklin,  N.  J. ; 
near  Germantown,  Pa.;  Jones's  Falls,  Maryland.  Oblique 
prisms  from  near  Greenwood  are  sometimes  six  or  seven 
inches  in  diameter.  Western  North  Carolina  affords  much 
mica  for  commerce. 


268 


DESCRIPTIONS   OF  MINERALS. 


A  green  variety  occurs  at  Unity,  Maine,  near  Baltimore, 
Md.,  and  at  Chestnut  Hill,  Pa.  Prismatic  mica  is  found  at 
Eussel,  Mass. 

On  account  of  the  toughness,  transparency,  and  the  thin- 
ness of  its  folia,  mica  was  formerly  used  in  Siberia  for  glass  in 
windows,  whence  it  has  been  called  Muscovy  glass.  It  is  in 
common  use  for  lanterns,  and  alsg  for  the  doors  of  stoves, 
and  other  purposes  which  demand  a  transparent  substance 
not  affected  by  heat. 

Lepidolite,  or  Lithia  mica.  Resembles  muscovite.  Color  rose-red, 
and  lilac  to  white  ;  in  crystalline  plates  and  aggregations  of  scales. 
It  contains  from  2  to  5  per  cent,  of  lithia,  and  hence  B.B.  imparts  a 
deep  crimson  color  to  the  flame. 

From  Rozena  in  Moravia  ;  Zinnwald  in  Bohemia  (the  Zinnwaldite]  ; 
Saxony  ;  the  Ural  ;  Sweden;  Cornwall;  Paris,  and  Hebron,  Maine; 
Chesterfield,  Mass.  ;  Middletown,  Conn.  The  red  mica  of  Goshen  is 
muscovite. 

Cryophyllite  has  the  same  constituents  as  lepidolite.  It  fuses  easily 
in  the  flame  of  a  candle.  From  Cape  Ann,  Mass. 

SCAPOLITE  GROUP. 

The  Scapolite  species  are  dimetric  in  crystallization, 
usually  white  in  color  or  of  some  light  shade,  and  analyses 
afford  alumina  and  lime  with  or  without  soda.  The  lime 
scapolites  are  unisilicate  in  ratio  ;  the  others,  containing 
alkali,  have,  with  one  exception,  more  silica  than  this  ratio 
requires. 

Wernerite.  —  Scapolite 

=  136°  7".  Cleavage  rather  indistinct  paral- 
lel with  i-i  and  /.  Also  massive,  sub- 
lamellar,  or  sometimes  faintly  fibrous 
in  appearance. 

Colors  light  ;  white,  gray,  pale  blue, 
greenish  or  reddish.  Streak  uncolored. 
Transparent  to  nearly  opaque.  Lustre 
usually  a  little  pearly.  H.  =  5-6.  G.  =• 
2-6-2-8. 

Composition.  (-J-(Ca,Na2)f  Al)2012  Si3= 
Silica  48-4,  alumina  28-5,  lime  18-1, 
soda  5-0—  100.  B.B.  fuses  easily  with  intumescence  to  a 
white  glass.  Imperfectly  decomposed  by  hydrochloric  acid. 


Dimetric.  1 


UNISILICATES.  269 

Diff*  Its  square  prisms  and  the  angle  of  the  pyramid  at 
summit  are  characteristic.  In  cleavable  masses  it  resembles 
feldspar,  but  there  is  a  slight  fibrous  appearance  often  dis- 
tinguished on  the  cleavage  surface  of  scapolite,  which  is 
peculiar.  It  is  more  fusible  than  feldspar,  and  has  higher 
specific  gravity.  Spodumene  has  a  much  higher  specific 
gravity,  and  differs  in  its  action  before  the  blowpipe.  Tabu- 
lar spar  is  more  fibrous  in  the  appearance  of  the  surface, 
and  is  less  hard ;  it  also  gelatinizes  with  acids. 

Obs.  Found  mostly  in  the  older  crystalline  rocks,  and  also 
in  some  volcanic  rocks.  It  is  especially  common  in  granular 
limestone.  Fine  crystals  occur  at  Grouverneur,  N.  Y.,  and 
at  Two  Ponds  and  Amity,  N.  Y. ;  at  Bolton,  Boxborough 
and  Littleton,  Mass.;  at  Franklin  and  Newton,  N.  J.  It 
occurs  massive  at  Marlboro',  Vt. ;  Westfield,  Mass. ;  Monroe, 
Ct.  Foreign  localities  are  at  Arendal,  Norway ;  Wiirmland, 
Sweden ;  Pagas  in  Finland,  and  also  at  Vesuvius,  whence 
come  the  small  crystals  called  meionite. 

Nuttallite,  Glaucolite,  are  varieties  of  this  species. 

Ekebergite  resembles  wernerite,  being  distinguishable  from  it  only 
by  chemical  analysis.  Dipyre  also  is  near  wernerite,  but  contains 
more  silica  and  10  per  cent,  of  soda ;  from  the  Pyrenees. 

Meionite,  a  lime  scapolite,  is  like  wernerite  in  its  crystals,  but  has 
the  formula  (^CafAl)2O12Si3,  being  a  true  unisilicate.  From  Monte 
Somma. 

Mizzonite  and  Marialite  resemble  meionite.  Paranthine  and  Sar- 
colite  are  other  related  unisilicate  species. 

Nephelite. — Nepheline. 

Hexagonal.  In  hexagonal  prisms  with  replaced  basal 
edges  ;  0Al— 135°  55'.  Also  massive  ;  sometimes  thin  col- 
umnar. 

Color  white,  or  gray,  yellowish,  greenish,  bluish-red. 
Lustre  vitreous  or  greasy.  Transparent  to  opaque.  H.  = 
5-5-6.  G.  =2  -5-2  -65. 

Composition.  (Na2,  K2)A108Si2=  (if  Na  :  K=5  :  1)  Sili- 
ca 44-2,  alumina  33-7,  soda  16-9,  potash  5-2  =  100;  a  little 
lime  is  usually  present.  B.B.  fuses  quietly  to  a  colorless 
glass.  Decomposed  by  hydrochloric  acid,  and  the  solution 
gelatinizes  on  evaporation.  The  name  nephelite  alludes  to 
the  mineral  becoming  clouded  in  acid.  Nephelite  includes 
the  glassy  crystals  from  Vesuvius  called  Sommite,  and  also 
hexagonal  crystals  in  other  volcanic  rocks ;  and  a  massive 
variety,  of  greasy  lustre,  called  Elceolite,  from  the  Greek 


270  DESCRIPTIONS   OP  MINERALS. 


elaion,  oil.  Altered  crystals  are  in  part  the  mineral  Gie- 
seckite. 

Diff.  Distinguished  from  scapolite  and  feldspar  by  the 
greasy  lustre  when  massive,  and  its  forming  a  jelly  with 
acids  ;  from  apatite  by  the  last  character,  and  also  its  hard- 
ness. 

Obs.  Nephelite  is  the  prominent  constituent  of  nephelin- 
doleryte  or  nephelinyte,  and  phonolyte,  and  occurs  also  in 
some  other  eruptive  rocks  ;  and  it  also  enters  into  the  con- 
stitution of  miascyte,  zircon-syenyte,  metamorphic  rocks. 
Among  the  localities  are  Vesuvius  and  C.  di  Bove,  in  Italy  ; 
Katzenbuckel,  near  Heidelberg ;  Aussig  in  Bohemia ;  and 
as  elaeolite,  Brevig,  Norway ;  in  Siberia ;  in  the  Ozark 
Mountains,  Arkansas  ;  in  Litchfield,  Maine. 

Cancrinite.  Crystals  like  those  of  nephelite,  and  compo- 
sition similar,  except  the  presence  of  some  carbonates  and 
usually  water.  Color  white,  gray,  yellow,  green,  blue,  or 
reddish;  H.  =5-6.  G.  rr2-4-2;5.  On  account  of  the  car- 
bonates it  effervesces  in  acids.  B.B.  fuses  very  easily. 

Occurs  in  crystalline  rocks  at  Miask  in  the  Ural ;  in  Nor- 
way ;  Transylvania  ;  and  at  Litchfield  in  Maine,  with  elaeo- 
lite and  sodalite.  Supposed  to  be  altered  nephelite. 

Microsommite  is  near.     Sommite  (nephelite). 

Sodalite. 

Isometric.  In  dodecahedrons  ;  cleavage  dodecahedral. 
Color  brown,  gray,  or  blue.  H.  =6.  G.  =2  -25-2  -3. 

Composition.  Na2  Al  08  Si2  + J  NaCl=Silica  37*1,  alumina 
31-7,  soda  19-2,  sodium  4-7,  chlorine  7 -3  =  100.  B.B.  fuses 
with  intumescence  to  a  colorless  glass.  Decomposed  by  hy- 
drochloric acid,  and  the  solution  gelatinizes  on  evaporation. 

Occurs  in  eruptive  and  metamorphic  rocks.  Found  in  Si- 
cily ;  near  Lake  Laach  ;  at  Miask  ;  in  Norway ;  West  Green- 
land ;  of  a  blue  color  at  Litchfield,  Me. ;  and  lavender-blue 
at  Salem,  Mass. 

Hauynite  (or  Hauyne)  and  Nosite  (or  Nosean)  are  related  minerals 
from,  lavas  or  other  eruptive  rocks  ;  and  Ittnerite  is  altered  haiiynite 
or  nosite.  Isometric.  In  dodecahedrons.  Color  bright  blue,  occasion- 
ally greenish.  Transparent  to  translucent.  H.=6.  G.=2'4-25. 

Lapis-Lazuli. — Ultramarine. 

Isometric.  In  dodecahedrons;  cleavage  imperfect.  Usual- 
ly massive,  Color  rich  Berlin  or  azure  blue.  Lustre  vitre- 
ous. Translucent  to  opaque.  H.=5'5.  G.  =243-2-5. 


UNISILICATES.  271 

Composition.  Silica  45-5,  alumina  31-8,  soda  9-1,  lime 
3 '5,  iron  0'8,  sulphuric  acid  5*9,  sulphur  0*9,  chlorine  0*4, 
water  0-1--98-0.  B.B.  fuses  to  a  white  translucent  or 
opaque  glass,  and  if  calcined  and  reduced  to  powder  loses 
its  color  in  acids  ;  is  decomposed  with  the  evolution  of 
hydrogen  sulphide,  and  the  solution  gelatinizes  on  evapora- 
tion. The  color  of  the  mineral  is  supposed  to  be  due  to 
sodium  sulphide.  The  mineral  is  not  homogeneous,  but  the 
exact  nature  of  the  ultramarine  species  at  the  basis  of  it  is 
not  yet  ascertained. 

Obs.  Found  in  syenyte  and  granular  limestone,  and  is 
brought  from  Persia,  China,  Siberia,  and  Bucharia.  The 
specimens  often  contain  scales  of  mica  and  disseminated 
pyrites. 

The  richly  -  colored  lapis -lazuli  is  highly  esteemed  for 
costly  vases,  and  for  inlaid  work  in  ornamental  furniture. 
It  is  also  used  in  the  manufacture  of  mosaics.  When  pow- 
dered it  constitutes  a  beautiful  and  durable  blue  paint, 
called  Ultramarine,  which  has  been  a  costly  color.  The 
discovery  of  a  mode  of  making  an  artificial  ultramarine, 
quite  equal  to  the  native,  has  aiforded  a  substitute  at  a  com- 
paratively cheap  rate.  This  artificial  ultramarine  consists 
of  silica  45-6,  alumina  23 '3,  soda  21-5,  potash  1-7,  lime 
trace,  sulphuric  acid  3-8,  sulphur  1*7,  iron  1-1,  and  chlorine 
a  small  quantity  undetermined.  It  has  taken  the  place  in 
the  arts,  entirely,  of  the  native  lapis-lazuli. 

Zieucite. — Amphigene. 

Dimetric.  Form  very  nearly  that  of  the  trapezohedron 
represented  in  the  figure.  Cleavage  imper- 
fect. Usually  in  dull  glassy  crystals,  of  a 
grayish  color ;  sometimes  opaque- white,  dis- 
seminated through  lava.  Translucent  to 
opaque.  H.^5'5-6.  G.=2'5.  Brittle. 

Composition.     K2  Al  0,2  Si4  —  Silica    55*0, 
alumina  23-5,  potash  21-53=100.     B.B.  infu- 
sible.  Moistened  with  cobalt  nitrate  and  ig- 
nited assumes  a  blue   color.     Decomposed  by  hydrochloric 
acid,  without  gelatinizing. 

Diff.  Distinguished  from  analcite  by  its  hardness  and  in- 
fusibility. 

Obs.  In  volcanic  rocks,  and  abundant  in  those  of  Italy, 


272  DESCRIPTIONS    OF   MINERALS. 

especially  at  Vesuvius,  where  crystals  occur  from  the  size  of 
a  pin's  head  to  a  diameter  of  an  inch.  Also  found  in  the 
Leucite  Hills,  northwest  of  Point  of  Rocks,  Wyoming  Ter- 
ritory. 

The  name  leucite  is  from  the  Greek  leukos,  white. 


FELDSPAR  GROUP. 

I.  RELATIONS  OF  THE  SPECIES  OF  FELDSPAK. 
The  species  of  the  Feldspar  Group  are  related — 

A.  In  crystallization :  (1)  the  forms  heing  all  oblique ; 
(2)  the  angle  of  the  fundamental  rhombic  prism  /,  in  each, 
nearly  120°  ;    (3)  the  other  angles  differing  but  little,  al- 
though part  of  the  species   are  monoclinic   and  part   tri- 
clinic  ;  and  (4)  there  being  two  directions  of  easy  cleavage, 
one,  the  most  perfect,  parallel  to  the  basal  plane  0,  and  the 
other  parallel  to  the  shorter  diagonal  section,  with  the  in- 
tervening angle  either  90°  (as  in  the  monoclinic  species  or- 
thoclase  and  hyalophane),  or  nearly  90°   (as  in  the  triclinic 
species). 

B.  In  composition:  (1)  the  only  element  in  the  sesquiox- 
ide  state  being  aluminum,  and  those  in  the  protoxide  state 
either  calcium,  barium,  sodium,  or  potassium,  or  two  or 
three  of  these  bases  together;  (2)  the  ratio  of  1  atom  of  R 
to  1  of  R  being  constant ;  (3)  the  amount  of  silica  in  the 
species  increasing  with  the  proportion  of  alkali,  being  that 
of  a  unisilicate  in  the  pure  lime-feldspar,  anorthite,  that' 
of  a  tersilicate  in  the  soda-feldspar,  albit'e,  or  potash-feldspar, 
orthoclase,  and  so  directly  proportioned  to  the  alkali,  that 
the  amount  in  any  lime-and-soda  feldspar  may  be  deduced 
by  taking  the  lime  (or  calcium)  as  existing  in  the  state  of  a 
unisilicate,  and  the  soda  in  that  of  a  tersilicate,  and  adding 
the  two  together. 

Anorthite  has  the  formula  CaAl  08  Sis. 
Albite  "  "       Na2Al  016  Si6. 

The  constitution  of  a  species  containing  Ca  and  Na»  in 
the  ratio  of  1  to  1  for  the  protoxide  portion  may  be  ob- 


FELDSPAR   GROUP.  273 

tained  as  follows.  Adding  together  the  anorthite  and  albite 
formulas,  we  have  CaNa2Al2  024  Si8 ;  then  dividing  by  2,  the 
formulas  becomes  £Ca|Na2Al  012  Si4,  which  expresses  the 
composition  of  andesite.  With  3  parts  of  the  Ca  unisili- 
cate,  and  1  of  the  Na2  tersilicate,  the  composition  is  that 
of  labradorite.  So  it  is  for  other  combinations,  that  is  for 
other  species  between  anorthite  and  albite  in  composition. 

The  quantivalent  ratio  for  the  R,  Al,  Si,  in  the  several 
species  of  the  group,  is  as  follows :  V  means  triclinic  in 
crystallization,  and  IV  monoclinic. 


SYSTEM  OP  SYSTEM  OP 

CRY6TAI.L1ZA-  KAT10.      CRYSTALLIZA- 

TION. TION. 


Anortliite,  1:3:4  V,  Oligoclase,    1:3:9  V. 

Labradorite,  1:3:6  V,  Albite,           1:3:12  V. 

Hyalophane,  1:3:8  IV,  Microcline,   1  : 3  : 12  V. 

Andesite,  1:3:8  V,  Orthoclase,   1  : 3  : 12  IV. 

These  are  the  normal  ratios  ;  but  there  is  some  variation 
from  them  in  the  analyses,  part  of  which  is  variation  in 
actual  composition,  and  part  a  result  of  interlamination  or 
mixture  of  two  feldspars  together.  Thus,  orthoclase  occurs 
mixed  with  microcline,  albite,  or  oligoclase.  But  while  such 
mixtures  account  for  the  soda  found  in  some  analyses  of 
orthoclase,  it  does  not  for  that  in  all,  since  soda  does  occur 
in  many  specimens  of  pure  orthoclase,  replacing  part  of  the 
potash.  It  is  the  same  with  the  triclinic  feldspar  micro- 
cline, which  has  the  composition  of  orthoclase,  and  may 
have  the  alkali  portion  all  potash  or  part  soda,  one  analysis 
of  typical  microcline  giving  only  0-48  of  soda.  It  is,  hence, 
not  safe  to  calculate  the  percentage  of  orthoclase  present 
in  a  feldspar  from  the  percentage  of  potash.  Moreover, 
potash  is  present  in  much  albite. 

The  above  ratios  show  that  anorthite  has  for  the  ratio 
between  R  +  R  and  Si,  4  :  4,  or  1  : 1,  as  in  true  unisilicates  ; 
while  in  albite  and  orthoclase,  the  same  ratio  is  4  : 12  or 
1 :  3,  that  of  a  tersilicate,  as  above  stated. 

0.  In  physical  characters :  the  hardness  being  between  6 


274  DESCRIPTIONS   OF   MINERALS. 

and  7;  the  specific  gravity,  between  2-44  and  2-75  ;  lustre 
vitreous,  but  often  pearly  on  the  face  of  perfect  cleavage  ; 
and  each  species  transparent  to  subtranslucent. 

II.  ACIDIC  AND  BASIC  FELDSPAKS. 

Oligoclase,  albite,  and  orthoclase  are  called  acidic  feld- 
spars, because  of  the  large  amount  of  the  acidic  element, 
silicon,  in  their  constitution,  analyses  giving  60  to  70  per 
cent,  of  silica ;  and  labradorite  and  anorthite  are  called 
basic  feldspars,  the  amount  of  silica  being  42  to  55  per 
cent.  Correspondingly,  eruptive,  and  metamorphic  rocks 
in  which  either  of  the  acidic  feldspars  is  a  prominent  con- 
stituent— for  example,  granite,  gneiss,  trachyte,  true  por- 
phyry— are  called  acidic  rocks  ;  while  those  rocks  in  which 
basic  feldspars  are  constituents — like  doleryte,  and  a  large 
part  of  eruptive  rocks — are  called  basic  rocks. 

III.  DISTINCTIONS  OF  THE  TKICLINIC  FELDSPAKS. 

The  triclinic  feldspars  are  distinguished  from  the  mono- 
clinic  (e.  g.  orthoclase)  by  the  occurrence  of  very  line  stria- 
tions  on  the  cleavage  surface,  sometimes  too  fine  to  be  seen 
without  a  good  pocket-lens.  These  striations  are  due  to 
multiple  twinning  parallel  to  the  other  cleavage  face,  as  ex- 
plained on  page  57.  They  are  rarely  absent  from  triclinic 
feldspar  crystals.  They  are  best  brought  out  by  transmitted 
polarized  light,  in  which  a  transverse  section  of  the  crys- 
tal is  seen  banded  with  spectrum  colors,  each  band  corre- 
sponding to  one  plate  of  the  twin  structure. 

The  triclinic  feldspars,  andesite  excepted,  may  be  dis- 
tinguished from  one  another  by  an  optical  method  when 
the  cleavage  direction  can  be  made  out.  For  this  purpose 
a  plate  is  prepared  parallel  to  the  plane  of  easiest  cleavage. 
In  such  a  plate  the  multiple  twinning  is  parallel  to  the  other 
cleavage  plane,  or  the  shorter  diagonal.  When  the  plate  is 
placed  on  the  stage  of  a  polariscope,  between  crossed  Nicol- 
prisms,  as  the  stage  is  revolved,  the  adjoining  bands  of  color 
become  dark  alternately,  and  the  angle  through  which  the 


FELDSPAR  GROUP.  275 

plate  has  to  be  revolved  for  the  change  between  consecutive 
bands  varies  for  different  species,  it  being  54°  to  74°  for 
anorthite,  10°  to  14°  for  labradorite,  4°  to  8°  for  oligoclase, 
6J°  to  8°  for  albite,  and  30°  for  microcline.  The  shorter 
diagonal  of  the  crystal  bisects  this  angle,  so  that  the  angle 
made  with  this  diagonal  is  27°  to  37°  for  anorthite,  5°  to 
7°  for  labradorite,  2°  to  4°  for  oligoclase,  3£°  to  4°  for  albite, 
and  15°  for  microcline.  Obtaining  cleavage  plates  for  such 
measurements  in  the  case  of  slices  for  microscope  investiga- 
tion, is  seldom  possible,  and  when  not  so,  the  only  certain  re- 
source for  the  distinguishing  of  triclinic  feldspars  is  chemical 
analysis.  These  feldspars  have  been  called  plagioclase  (from 
the  Greek  words  for  oblique  and  fracture),  as  if  all  were  of 
one  species.  The  term  is  a  convenient  cover  for  ignorance. 

IV.  DISTINCTIONS  FROM  OTHER  MINERALS.  When  in 
crystals,  the  form  is  sufficient  to  determine  a  feldspar ;  so  also 
the  facl^jf  two  unequal  cleavages  inclined  to  one  another  at 
84°  to  90°,  one  of  them  quite  perfect.  No  fibrous,  columnar, 
or  micaceous  varieties  are  known.  They  differ  from  rho- 
donite, by  the  absence  of  a  manganese  reaction  ;  from  spodu- 
mene,  by  the  absence  of  a  lithia  reaction  as  well  as  cleavage 
angles;  from  scapolite,  by  form,  the  cleavage  angles,  the 
more  difficult  fusibility ;  from  nephelite,  by  form,  and  also 
in  difficult  fusibility,  and  not  gelatinizing  with  acids,  ex- 
cept in  the  case  of  anorthite  and  labradorite,  -which  fuse 
with  but  little  more  difficulty  than  nephelite,  and  often  will 
gelatinize. 

Anorthite.— Indianite.     Lime  Feldspar. 

Triclinic.  Angle  between  the  two  cleavage  planes  85°  50' 
and  94°  10'.  Crystals  tabular.  Also  massive  granular  or 
coarse  lamellar.  Color  white,  grayish,  or  reddish. 

Composition.  CaAl  08  Si2= Silica  43*1,  alumina  36-8,  lime 
20-1^100.  B.B.  fuses  with  much  difficulty  to  a  colorless 
glass  ;  decomposed  by  hydrochloric  acid,  the  solution  gela- 
tinizes on  evaporation. 

Obs.  Occurs  in  basic  eruptive  rocks;  also  in  some  meta- 


276  DESCRIPTIONS   OF    MINERALS. 

morphic  rocks.  Found  in  the  lava  of  Vesuvius  ;  in  the 
Tyrol ;  Faroe  Islands,  Iceland  ;  in  imbedded  crystals  in  some 
doleryte  of  the  Connecticut  Valley. 

At  Hanover,  N.  H.,  anorthite  crystals  occur  altered  to  a  silicate 
which  afforded,  in  an  analysis  by  Hawes,  only  2 '2  of  lime,  and,  in  place 
of  the  rest  of  this  ingredient,  711  of  potash,  3-77  of  soda,  1  10  of  iron- 
sesquioxide,  and  2  '07  of  water,  with  80  05  of  alumina  and  52  52  of 
silica  ;  which  compound,  if  the  water  be  made  basic,  has  the  ratio 
nearly  of  labradorite,  though  distinct  from  that  species  in  the  alkalies, 
and  also  in  specific  gravity,  which  is  2  "96  or  very  nearly  3.  It  has  some 
relation  to  zoisite,  and  to  typical  saussurite,  but  is  widely  different 
in  constituents  and  ratio ;  it  is  related  also  to  jadeite.  (See  page 
263.) 

Labradorite. — Lime-soda  Feldspar.     Labrador  Feldspar. 

Triclinic.  Angle  between  the  cleavage  planes  93°  20'  and 
86°  40'.  Usually  in  cleavable  massive  forms. 

Color  dark  gray,  brown,  or  greenish  brown  ;  also  white  or 
colorless.  Often  a  series  of  bright  chatoyant  colors  from  in- 
ternal reflections,  especially  blue  and  green,  with  more  or 
less  of  yellow,  red,  and  pearl-gray. 

f  Composition.  |CaJNa2Al  010Sia= Silica  52;9,  alumina  30 -3, 
lime  12*3,  soda  4-5  =  100.  Sometimes  contains  a  little  potash 
in  place  of  the  soda.  B.B.  fuses  quite  easily  to  a  colorless 
glass.  Only  partially  decomposed  by  hydrochloric  acid. 

Obs.  A  constituent  of  the  larger  part"  of  eruptive  rocks,  as 
doleryte,  and  amphigenyte,  and  many  lavas  ;  and  also  of  some 
metamorphic  rocks.  Occurs  as  an  ingredient  in  part  of  the 
Archaean  rocks  in  North  America,  and  was  named  from  its 
first  discovery  in  Labrador. 

Andesite.  Triclinic.  Angle  between  the  cleavage  planes  87°-88°. 
Near  labradorite  in  composition.  The  formula  iCa|Na2A1012  Si4  = 
Silica  59-8,  alumina  25  5,  lime  7'0,  soda  7 -7=100-0. 

HycdopJiane.  Monoclinic,  and  hence  angle  between  the  cleavage 
planes  90°.  A  baryta  feldspar  ;  the  formula  like  that  of  andesite,  ex- 
cepting the  substitution  of  Ba  for  Caand  K2  for  Na2.  It  has  been  found 
in  the  Binnenthal,  Switzerland,  and  at  Jakobsberg,  Sweden. 

A  baryta-feldspar,  having  the  ratio  of  andesite,  1:3:8,  has  been 
described  which  is  tridinic,  and  approaches  oligoclase  in  optical  char- 
acters. 

Oligoclase.— Soda-lime  Feldspar. 

Triclinic.  Angle  between  the  cleavage  planes  93°  50'  and 
86°  10'.  Commonly  in  cleavable  masses.  Also  massive. 

Color  usually  white,  grayish  white,  grayish  green,  green- 
ish, reddish.  Transparent,  subtranslucent.  H.=6-7.  G-.= 
2  -5-2  -7. 


FELDSPAR    GROUP. 


277 


Composition.  JCajNa.,Al  014  Si5= Silica  61-9,  alumina  24-1, 
lime  5*2,,  soda  8*8  =  100.  A  portion  of  the  soda  is  usually 
replaced  by  potash.  B.  B.  fuses  without  difficulty  ;  not  de- 
composed by  acids. 

Obs.  It  occurs  in  granite,  syenyte,  and  various  meta- 
morphic  rocks,  especially  those  containing  much  silica  :  and 
in  such  case  usually  associated  with  orthoclase.  Sunstone  is 
in  part  oligoclase  containing  disseminated  scales  of  hematite 
giving  hright  reflection  from  the  interior  of  the  stone.  Oc- 
curs in  Norway.  Moonstone  is  in  part  a  whitish  opalescent 
variety.  Oligoclase  occurs  at  Unionville,  Pa.;  Haddam, 
Conn.  ;  Mineral  Hill,  Del.  ;  Chester,  Mass.,  etc. 

Albite. 

Triclinic.  Angle  between  the  cleavage  planes  93°  36', 
and  83°  24'.  Figures  1  to  6  represent  some  of  its  forms ; 


2  and  3  are  twin  crystals.  The  crystals  are  usually  more  or 
less  thick  and  tabular.  Also  massive,  with  a  granular  or 
lamellar  structure.  Color  white  ;  occasionally  light  tints  of 
bluish  white,  grayish,  reddish  and  greenish.  Transparent 
to  subtranslucent. 

Composition.  Na2Al  016Si,j= Silica  68-6,  alumina  19*6, 
soda  11 -8 =100-0.  B.B.  fuses  to  a  colorless  or  white  glass, 
imparting  an  intense  yellow  to  the  flame.  Not  acted  upon 
by  acids. 


278  DESCRIPTIONS   OF  MINKRALS. 

Cleavelandite  is  a  lamellar  variety  occurring  in  wedge- 
shaped  masses  at  the  Chesterfield  albite  vein,  Mass. 

Obs.  Albite  occurs  in  some  granites  and  gneiss,  and  is 
most  abundant  in  granite  veins.  Fine  crystals  occur  at 
Middletown  and  Haddam,  Conn.,  at  Goshen,  Mass.,  and 
Granville,  N.  Y.  ;  Unionville,  Delaware  County,  Penn. 

The  name  albite  is  from  the  Latin  albus,  white. 

Microcline. 

A  potash-i eldspar,  very  close  to  the  following  species  in 
angles,  and  also  in  physical  characters,  and  identical  with  it 
in  composition.  But  it  is  very  slightly  triclinic,  the  angle 
between  its  cleavage  planes  varying  but  16'  from  90°  ;  and 
hence  its  cleavage  surface  shows  usually  the  fine  striations 
exhibited  with  rare  exceptions  by  all  the  triclinic  feldspars. 
Colors  white,  flesh-red,  copper-green.  The  last  is  what  has 
been  called  Amazon-stone  ;  as  heat  destroys  the  color  it  has 
been  supposed  to  be  of  organic  origin. 

Occurs  in  the  zircon-syenyte  of  Norway  ;  also  in  the  Urals  ; 
Greenland;  Labrador;  Leverett,  Mass.;  Redding,  Conn.; 
Delaware  ;  Chester  County,  Penn. ;  White  Mountain  Notch, 
green  ;  Pike's  Peak,  Amazon-stone ;  Magnet  Cove,  Ark. 

Orthoclase. — Common  Feldspar. 

Monoclinic  ;  and  hence  angle  between  the  cleavage  planes 
90°.  Figures  1  to  4  represent  common  forms,  and  5  to  8 
twin  crystals.  Usually  in  thick  prisms,  often  rectangular, 
and  also  in  modified  tables.  Also  massive,  with  a  granular 
structure,  or  coarse  lamellar ;  also  fine-grained  almost  flint- 
like  in  compactness.  Colors  light ;  white,  gray,  and  flesh- 
red  common  ;  also  greenish  and  bluish-white  and  green. 

Composition.  K2  Al  016  Si6  =  Silica  64-7,  alumina  18-4, 
potash  16 '9 =100.  Soda  sometimes  replaces  a  portion  of 
the  potash.  B.B.  fuses  with  difficulty;  not  acted  on  by 
acids. 

Common  feldspar  includes  the  common  subtranslucent 
varieties ;  Adularia,  the  white  or  colorless  subtransparent 
specimens,  a  name  derived  from  Adula,  one  of  the  highest 
peaks  of  St.  Gothard.  Sanidin  or  glassy  feldspar  includes 
transparent  vitreous  crystals,  found  in  tradhytes  and  lavas ; 
but  some  of  the  "glassy  feldspar"  belongs  to  the  species 
anorthite.  Loxodase  is  a  grayish  variety  with  a  pearly  or 
greasy  lustre  that  contains  much  soda. 


FELDSPAR    GROUP. 


279 


Moonstone  is  an  opalescent  variety  of  adularia,  having 
when  polished  peculiar  pearly  reflections.  Sunstone  is  simi- 
lar; but  contains  minute  scales  of  mica.  A  venturing  feld- 


spar often  owes  its  iridescence  to  minute  crystals  of  specular 
or  titanic  iron,  or  limonite.  Sunstone  and  moonstone  are 
mostly  oligoclase,  and  so  is  a  large  part  of  aventurine  feld- 
spar. 

Diff.  Distinguished  from  the  other  feldspars  by  its  right- 
angled  cleavage  and  the  absence  of  striated  surfaces. 

Obs.  Orfchoclase  is  one  of  the  constituents  of  granite,  sye- 
nyte,  gneiss,  and  other  related  rocks  ;  also  of  porphyry,  and 
trachyte  ;  and  it  often  occurs  in  these  rocks  in  imbedded 
crystals.  St.  Lawrence  County,  N.  Y.,  affords  fine  crystals  ; 
also  Orange  County,  N.  Y. ;  Haddam  and  Middletown, 
Conn.;  Acworth,  N.  H.  ;  South  Royalston  and  Barre, 
Mass.,  besides  numerous  other  localities.  Green  feldspar 
occurs  at  Mount  Desert,  Me.;  an  aventurine  feldspar  at 
Leiperville,  Penn. ;  adularia  at  Haddam  and  Norwich, 
Conn.,  and  Parsonsfield,  Me.  A  fetid  feldspar  (sometimes 
called  necronite)  is  found  at  Koger's  Rock,  Essex  County ; 
at  Thomson's  quarry,  near  196th  Street,  New  York  City, 
and  21  miles  from  Baltimore.  Carlsbad  and  Elbogen  in  Bo- 
hemia, Baveno  in  Piedmont,  St.  Gothard,  Arendal  in  Nor- 
way, Land's  End,  and  the  Mourne  Mountains,  Ireland,  are 
some  of  the  more  interesting  foreign  localities. 


280  DESCRIPTIONS   OF   MINERALS. 

Felsite  is  compact,  uncleavable  orthoclase,  having  the 
texture  of  jasper  or  flint,  which  it  much  resembles.  It  often 
contains  some  disseminated  silica.  It  occurs  of  various  col- 
ors, as  white,  gray,  brown,  red,  brownish  red  and  black,  and 
is  sometimes  banded.  It  is  distinguished  from  flint  or  jas- 
per by  its  fusibility. 

Felsite  is  the  material  of  beds  or  strata  in  some  rock  for- 
mations, and  also  of  dikes  or  masses  of  eruptive  rocks.  It  is 
the  base  of  much  red  porphyry.  The  vicinity  of  Marblehead, 
Mass.,  is  one  of  its  localities. 

The  name  feldspar  is  from  the  German  word  Feld,  mean- 
ing field.  It  is,  therefore,  wrong  to  write  it  felspar. 

Orthoclase  is  used  extensively  in  the  manufacture  of  por- 
celain. The  large  granite  veins  of  Middletown  and  Port- 
land, Conn.,  are  quarried  in  several  places  for  both  orthoclase 
and  quartz  for  this  purpose  ;  the  places  are  often  called 
China-stone  quarries. 

Kaolin.  This  name  is  applied  to  the  clay  that  results 
from  the  decomposition  of  feldspar.  See  Kaolinite,  p.  310. 

m.  SUBSILICATES. 

In  the  Subsilicates,  as  stated  on  page  242,  the  combin- 
ing or  quantivalent  ratio  between  the  bases  and  silica  is  1 
to  less  than  1.  In  Chondrodite,  the  first  of  the  following 
species,  the  ratio  is  4:3;  in  Tourmaline,  Andalusite,  Cya- 
nite,  and  Fibrolite,  3  :  2.  Analyses  of  Andalusite  obtain  1 
of  alumina,  Al  03,  to  1  of  silica,  Si  02,  giving  the  oxygen 
ratio  for  bases  and  silica  3  :  2.  This  is  the  composition  also 
of  cyanite  and  fibrolite  ;  so  that  the  three  species,  anda- 
lusite,  cyanite,  and  fibrolite  are  the  same  in  constituents 
and  atomic  ratio  while  differing  in  crystalline  form,  exem- 
plifying a  case  of  trimorphism  among  minerals. 

The  ratio  3  :  2  exists  also  in  Topaz,  Euclase  and  Da- 
tolite  in  Titanite  or  sphene,  and  in  Keilhauite.  In  Stau- 
rolite,  the  ratio  was  formerly  regarded  as  2:1;  but  the 
most  recent  analyses,  those  of  Eammelsberg,  give  11  :  6,  or 
1$:1. .  In  datolite  and  tourmaline  the  basic  constituents 
include  boron  ;  in  titanite  and  keilhauite,  titanium  ;  in  da- 


8UBSILICATES.  281 

tolite,  euclase,  and  part  of  staurolite,  hydrogen,  that  is,  the 
hydrogen  of  the  water  found  on  analysis.  In  chondrodite, 
topaz,  and  some  tourmaline,  fluorine  replaces  part  of  the 
oxygen. 

Chondrodite. — Humite  in  part  (Scacchi's  Type  II). 

Monoclinic.  Cleavage  indistinct.  Usually  in  imbedded 
grains  or  masses.  Color  light  yellow  to  brownish  yellow,  yel- 
lowish red,  and  garnet-red.  Lustre  vitreous,  inclining  a  little 
to  resinous.  Streak  white,  or  slightly  yellowish  or  grayish. 
Translucent  or  subtranslucent.  Fracture  uneven.  H/=6- 
6-5.  G.=3-l-3-25. 

Composition.  Mgs  0,4  Si3 ;  but  a  portion  of  the  magnesium 
replaced  by  iron,  and  a  part  of  the  oxygen  by  fluorine.  A 
specimen  from  Brewster's,  New  York,  afforded  Silica  34'1, 
magnesia  53-7,  iron  protoxide  7*3,  fluorine  4-2,  with  0-48  of 
alumina =99*72. 

B.B.  infusible.  Decomposed  by  hydrochloric  acid  ;  the 
solution  gelatinizes  on  evaporation. 

Diff.  As  it  cccurs  only  in  limestone  it  will  hardly  be  con- 
founded with  any  species  resembling  it  in  color  when  the 
gangue  is  present.  It  does  not  fuse  lil^e,  tourmaline  or  gar- 
net, some  brownish-yellow  varieties  of  which  it  approaches 
in  appearance.  The  name  is  from  the  Greek  chondros,  a 
grain. 

Obs.  It  is  abundant  in  the  adjoining  counties,  Sussex,  N.  J., 
and  Orange,  N.  Y.,  occurring  at  Sparta  and  Bryam,  N.  J., 
and  in  Warwick  and  other  places  in  N.  Y. ;  at  the  Tilly 
Foster  Iron  Mine,  Brewster's,  Putnam  County,  N..Y.,  it  is 
very  abundant.  At  Vesuvius  it  occurs  in  small  crystals. 

The  species  was  early  named  Chondrodite,  from  Finland 
specimens  ;  soon  afterward  small  crystals,  found  in  the  lavas 
of  Somma  (Vesuvius),  were  named  Humite,  and  both  were 
referred  to  the  same  species.  It  has  recently  been  ascer- 
tained that  under  this  species,  two  species  of  different  an- 
gles and  form,  but  related  composition  and  physical  charac- 
ter, are  included.  For  these  species  the  names  Humite  and 
Clinohumite  have  been  adopted. 

Humite  is  orthorhombic,  and  embraces  part  of  the  Humite 
crystals  of  Vesuvius  (Scacchi's  Type  I.),  and  some  large 
coarse  chondrodite-like  crystals  found  at  Brewster's,  N.  Y. 

Clinohumite  is  monoclinic,  and  includes  Scacchi's  Type  III. 


282 


DESCRIPTIONS    OF   MINERALS. 


of  Humite  from  Vesuvius,  and  fine  chondrodite-like  crystals 
from  Brewster's. 

Tourmaline. 

Rhombohedral.  Usual  in  prisms  of  3,  6,  9,  or  12  sides, 
terminating  in  a  low  3-sided  pyramid.  The  sides  of  the 
prisms  are  often  rounded  and  striated.  Other  forms  are 
shown  in  the  figures.  The  common  pyramid  is  the  rhoinbo- 


1. 


2. 


hedron  — J  in  the  figures,  the  angle  of  which  is  133°  8'.  The 
crystals  often  have  unlike  secondary  planes  at  the  two  ex- 
tremities, as  shown  in  figure  3.  Occurs  also  compact  mas- 
sive, and  coarse  columnar,  the  columns  sometimes  radiating 
or  divergent  from  a  centre. 

Color  black,  blue-black,  and  dark  brown,  common  ;  also 
bright  and  pale  red,  grass-green,  cinnamon-brown,  yellow, 
gray,  and  white.  Sometimes  red  within  and  green  externally, 
or  one  color  at  one  extremity  and  another  at  the  other. 
Transparent ;  usually  translucent  to  nearly  opaque.  Di- 
chroic.  Lustre  vitreous,  inclining  to  resinous  on  a  surface 
of  fracture.  Streak  uncolored.  Brittle  ;  the  crystals  often 
fractured  across  and  breaking  very  easily.  H.=  7*0-7  *5.  G. 
=  3-33. 

Composition.  (R3,B2,R,)  05,  Si2,  in  which  R  includes,  in 
different  varieties,  Fe,  Mg,  Na2,  with  often  traces  also  of  Ca, 
Mn,  K2,  Li2;  R  includes  aluminum,  with  some  boron  in  the 
trioxide  state  replacing  =41 ;  and  a  little  of  the  oxygen  is 
sometimes  replaced  by  fluorine. 

A  black  tourmaline  from  Haddam  afforded  on  analysis, 
Silica  37-50,  boron  trioxide  (by  loss)  9-02,  alumina  30-87, 
iron  protoxide  8 '54,  magnesia  8 -60,  lime  1-33,  soda  1-60, 
potash  0  -73,  water  1  -81  =  100.  A  red  tourmaline  from  Paris, 
Maine,  afforded  Fluorine  1-19,  silica  41-16,  boron  trioxide 
(by  loss)  8-93,  alumina  41-83,  manganese  protoxide  0-95, 
magnesia  0-61,  soda  1 '37,  potash  217,  lithia  0-41,  water  2-57 
=100. 

Tourmaline  varies  much  in  color  owing  to  its  variations  in 


SUBSILICATES.  283 

composition  ;  the  dark  contain  much  iron  and  the  light 
colors  but  little.  Some  of  the  varieties  have  received  special 
names.  Rubellite  is  red  tourmaline;  and  Indicolite,  Hue  and 
bluish-black.  Schorl  formerly  included  the  common  black 
tourmaline,  but  the  name  is  not  now  used. 

The  presence  of  boron  trioxide  is  the  most  remarkable 
point  in  the  constitution  of  this  mineral.  The  colorless,  red, 
and  pale-greenish  kinds  usually  contain  lithia.  B.B.  the 
darker  varieties  fuse  with  ease,  and  the  lighter  with  difficulty. 
On  mixing  the  powdered  mineral  with  potassium  bisulphate 
and  fluor  spar,  and  heating  B.B. ,  gives  a  green  flame  owing 
to  the  boron. 

Diff.  The  black  and  the  dark  varieties  generally,  are 
readily  distinguished  by  the  form  and  lustre  and  absence  of 
distinct  cleavage,  together  with  their  difficult  fusibility. 
The  black  when  fractured  often  appear  a  little  like  a  black 
resin.  The  brown  variety  resembles  garnet  or  idocrase,  but 
is  more  infusible.  The  red,  green,  and  yellow  varieties  are 
distinguished  from  any  species  they  resemble  by  the  crystal- 
line form,  the  prisms  of  tourmaline  always  having  3,  6,  9, 
or  12  prismatic  sides  (or  some  multiple  of  3).  The  electric 
properties  of  the  crystals,  when  heated,  is  another  remarka- 
ble character  of  this  mineral.  The  test  for  boron  is  always 
good. 

Obs.  Tourmalines  are  common  in  granite,  gneiss,  mica 
schist,  chlorite  schist,  steatite,  and  granular  limestone. 
They  usually  occur  penetrating  the  rock.  The  black  crys- 
tals are  often  highly  polished  and  at  times  a  foot  in  length, 
when  perhaps  of  no  larger  dimensions  than  a  pipe-stem,  or 
even  more  slender.  This  mineral  has  also  been  observed  in 
sandstones  near  basaltic  or  trap  dikes. 

Red  and  green  tourmalines,  over  an  inch  in  diameter  and 
transparent,  have  been  obtained  at  Paris  and  Hebron,  Me., 
besides  pink  and  blue  crystals.  These  several  varieties  oc- 
cur also,  of  less  beauty,  at  Chesterfield  and  Goshen,  Mass. 
Good  black  tourmalines  are  found  at  Norwich,  New  Brain- 
tree,  and  Carlisle,  Mass.  ;  Alsted,  Acworth,  and  Saddleback 
Mountain,  N.  H.  ;  Haddam  and  Monroe,  Conn.  ;  Sara- 
toga and  Edenville,  N.  Y.  ;- Franklin  and  Newton,  N.  J.; 
near  Union ville,  Chester,  and  Middletown,  Penn.  ;  trans- 
parent brown  at  Hunterstown,  Canada  East ;  amber-colored 
at  Fitzroy ;  black  at  Bathurst,  and  Elmsley,  Canada  West ; 
fine  greenish  yellow  at  G.  Calumet  I. 


284  DESCRIPTIONS   OP  MINERALS. 

Dark  brown  tourmalines  are  obtained  at  Orford,  N.  H.; 
in  thin  black  crystals  in  mica  at  Grafton,  N.  H.  ;  Monroe, 
Ct.  ;  Gouverneur  and  Amity,  N.  Y.  ;  Franklin  and  Newton, 
N.  J.  A  fine  cinnamon-brown  variety  occurs  at  Kings- 
bridge  and  Amity,  Orange  Co.,  N.  Y.  and  also  south  in  New 
Jersey.  A  gray  or  bluish-gray  and  green  variety  occurs  near 
Edenville. 

The  word  tourmaline  is  a  corruption  of  the  name  used  in 
Ceylon,  whence  it  was  first  brought  to  Europe.  Lyncurium 
is  supposed  to  be  the  ancient  name  for  common  tourmaline ; 
and  the  red  variety  was  probably  called  hyacinth. 

The  red  tourmalines,  when  transparent  and  free  from 
cracks,  such  as  have  been  obtained  at  Paris,  Me.,  are  of  great 
value  and  afford  gems  of  remarkable  beauty.  They  have 
all  the  richness  of  color  and  lustre  belonging  to  the  ruby, 
though  measuring  an  inch  across.  The  yellow  tourmaline, 
from  Ceylon  is  but  little  inferior  to  the'  real  topaz,  and  is 
often  sold  for  that  gem.  The  green  specimens,  when  clear 
and  fine,  are  also  valuable  for  gems.  Plates  from  pellucid 
crystals  cut  in  the  direction  of  a  vertical  plane  are  much 
used  for  polariscopes. 

Gehlenite.  Tetragonal,  like  the  scapolites,  and  grayish  green  in 
color.  G.  =2 -9-3 '07.  Formula  Ca3AlO)0Si,  with  some  of  the  Al  re- 
placed by  J"e,  and  some  of  the  Ca  by  Fe  and  Mg.  From  Mount 
Monzoni  in  the  Fassa  Valley. 

Andalusite. 

Trimetric.  In  rhombic  prisms,  which  are  nearly  square  ; 
/A/=90°  48'.  Cleavage  lateral;  sometimes  distinct.  Also 
massive  and  indistinctly  coarse  columnar,  but  never  fine 
fibrous. 

Colors  gray  and  flesh-red.  Lustre  vitreous,  or  inclining  to 
pearly.  Translucent  to  opaque.  Tough.  H.  — 7*5.  G.  = 
3-1-3-3. 

1.  2.  3.  4. 


Composition.  A105  Si = Silica  36-9,  alumina  63-1  =  100. 
B.B.  infusible.  Ignited  after  being  moistened  with  cobalt 
nitrate  assumes  a  blue  color.  Insoluble  in  acids. 


SUBSILICATES.  285 

CMastolite  and  made  are  names  given  to  crystals  of  anda- 
lusite  which  show  a  tessellated  or  cruciform  structure  when 
broken  across  and  polished.  The  above  figures  represent 
sections  of  crystals  from  Lancaster,  Mass.  The  structure  is 
owing  to  carbonaceous  impurities  distributed  in  the  crystal- 
lizing process  in  a  regular  manner  along  the  sides,  edges 
and  diagonals  of  the  crystal.  Their  hardness  is  sometimes 
as  low  as  3. 

Diff.  Distinguished  from  pyroxene,  scapolite,  spodumene, 
and  i'eldspar,  by  its  infusibility,  hardness,  and  form. 

Obs.  Most  abundant  in  clay  slate  and  mica  slate,  but  oc- 
curring also  in  gneiss.  Found  in  the  Tyrol,  Saxony,  Bavaria, 
etc. ;  also  in  Westford,  Mass. ;  Litchfield  and  Washington, 
Ct.  ;  Bangor,  Me.  ;  Leiperville,  Marple,  and  Springfield, 
Penn.  ;  and  chiastolite  at  Sterling  and  Lancaster,  Mass., 
and  near  Bellows  Falls,  Vermont.  This  species  was  first 
found  at  Andalusia  in  Spain. 

Pibrolite. — Sillimanite.     Bucholzite. 

Orthorhombic.  In  long,  slender  rhombic  prisms,  often 
much  flattened,  penetrating  the  gangue.  /A/=96°-98°. 
A  brilliant  and  easy  cleavage,  parallel  to  the  longer  diago- 
nal. Also  in  masses,  consisting  of  aggregated  crystals  or 
fibres.  Color  hair-brown  or  grayish  brown.  Lustre  vitre- 
ous, inclining  to  pearly.  Translucent  crystals  break  easily. 
H.=G-7.  G.=3-2-3-3. 

Composition.  A105Si,  as  for  andalusite,  =  Silica  36*9,  alu- 
mina 63-1=:  100.  Moistened  with  cobalt  nitrate  and  ig- 
nited assumes  a  blue  color.  Infusible  alone  and  with  borax. 

Diff.  Distinguished  from  tremolite  and  the  varieties  gen- 
erally of  hornblende  by  its  brilliant  diagonal  cleavage,  and 
its  infusibility  ;  from  kyanite  and  andalusite  by  its  brilliant 
cleavage,  its  fibrous  structure,  and  its  rhombic  crystalline 
form. 

Obs.  Found  in  gneiss,  mica  schist,  and  related  metamor- 
phic  rocks.  Occurs  in  the  Tyrol,  at  Bodenmais  in  Bavaria  ; 
at  the  White  Mountain  Notch  in  N.  H.;  at  Chester  and 
near  Norwich,  Conn.  ;  Yorktown,  N.  Y.  ;  Chester,  Bir- 
mingham, Concord,  Darby,  Penn. ;  in  North  Carolina  ;  and 
elsewhere.  Fibrolite  was  much  used  for  stone  implements 
in  Western  Europe  in  the  "  Stone  age  ; "  the  locality  whence 
the  material  was  derived  is  not  known. 


286  DESCRIPTIONS   OF   MINERALS. 


Cyanite.— Kyanite.     Disthene. 

Triclinic.  Usually  in  long  thin-bladed  crystals  aggre- 
gated together,  or  penetrating  the  gangue.  Sometimes  in 
short  and  stout  crystals.  Lateral  cleavage  distinct.  Some- 
times fine  fibrous. 

Color  usually  light  blue,  sometimes  having  a  blue  centre 
with  a  white  margin;  sometimes  white,  gray,  green,  or  even 
black.  Lustre  of  flat  face  a  little  pearly.  H.  =5-7*5,  greatest 
at  the  ends  of  the  prisms,  and  least  on  the  flat  face  of  the 
prism.  G.  =3-45-3-7. 

Composition.  A105Si,  as  for  andalusite,  =  Silica  36-9, 
alumina  63 '1  =  100.  Blowpipe  characters  like  those  of  an- 
dalusite. 

Diff.  Distinguished  by  its  infusibility  from  varieties  of 
the  hornblende  family.  The  short  crystals  have  some  re- 
semblance to  staurolite,  but  their  sides  and  terminations  are 
usually  irregular  ;  they  differ  also  in  their  cleavage  and 
lustre.  The  thin-bladed  habit  of  cyanite  is  very  character- 
istic. 

Obs.  Found  in  gneiss  and  mica  schist,  and  of  ten  accom- 
panied by  garnet  and  staurolite. 

Occurs  in  long-bladed  crystallizations  at  Chesterfield  and 
Worthington,  Mass. ;  at  Litchfield  and  Washington,  Conn. ; 
near  Philadelphia ;  near  Wilmington,  Delaware ;  and  in 
Buckingham  and  Spotsylvania  counties,  Va.  Short  crystals 
(sometimes  called  improperly  fibrolite)  occur  in  gneiss  at 
Bellows  Falls,  Vt.,  and  at  Westfield  and  Lancaster,  Mass. 

In  Europe,  at  St.  Gothard  in  Switzerland,  at  Greiner  and 
Pfitsch  in  the  Tyrol,  in  Styria,  Carinthia,  and  Bohemia. 
Villa  Rica  in  South  America  affords  fine  specimens. 

The  name  cyanite  is  from  the  Greek  Jcuanos,  a  dark-blue 
substance.  It  is  also  called  disthene,  in  allusion  to  the  un- 
equal hardness  in  different  directions,  and  when  white,  rlice- 
tizite. 

Kyanite  is  sometimes  used  as  a  gem,  and  has  some  resem- 
blance to  sapphire. 

Topaz. 

Trimetric.  /A  I— 124°  17'.  Rhombic  prisms,  usually  dif- 
ferently modified  at  the  two  extremities.  /A/=  124°  17'. 
Cleavage  perfect  parallel  to  the  base. 

Color  pale  yellow  ;  sometimes  white,  greenish,  bluish,  or 


8UBSILICATES. 


287 


reddish.     Streak  white.     Lustre  vitreous.     Transparent  to 
subtranslucent.     Pyro-electric.     H.  =  8.     G= 3-4-3-65. 

Composition.  Al  05  Si,  with  a  part  of  the  oxygen  replaced 
by  fluorine  =  Silica  16*2,  silicon  fluorid  28-1,  alumina  55 '7 


1. 


2. 


=  100.  An  analysis  of  one  specimen  afforded,  Silica  34'24, 
alumina  57 '45,  fluorine  14-99.  13. B.  infusible.  Some  kinds 
become  yellow  or  of  a  pink  tint  when  heated.  Moistened 
with  cobalt  nitrate  and  ignited  assumes  a  fine  blue  color. 
Insoluble  in  acids. 

Diff.  Topaz  is  readily  distinguished  from  tourmaline  and 
other  minerals  it  resembles  by  its  brilliant  and  easy  basal 
cleavage. 

Obs.  Pycnite  is  a  variety  presenting  a  thin  columnar  struc- 
ture and  forming  masses  imbedded  in  quartz.  The  PJiysalite 
or  Pyrophysalite  of  Hisinger  is  a  coarse,  nearly  opaque  va- 
riety, found  in  yellowish-white  crystals  of  considerable  di- 
mensions. This  variety  intumesces  when  heated,  and  hence 
its  name  from  phusao,  to  blow,  and  pur,  fire. 

Topaz  is  confined  to  metamorphic  rocks  or  to  veins  inter- 
secting them,  and  is  often  associated  with  tourmaline,  beryl, 
and  occasionally  with  apatite,  fluorite,  and  tin  ore. 

Fine  topazes  are  brought  from  the  Uralian  and  Altai 
mountains,  Siberia,  and  from  Kamschatka,  where  they  occur 
of  green  and  blue  colors.  In  Brazil  they  are  found  of  a  deep 
yellow  color,  either  in  veins  or  nests  in  lithomarge,  or  in 
loose  crystals  or  pebbles.  Magnificent  crystals  of  a  sky-blue 
color  have  been  obtained  in  the  district  of  Cairngorm,  in 
Aberdeenshire.  The  tin  mines  of  Schlackenwald,  Zinnwald, 
and  Ehrenfriedersdorf  in  Bohemia,  St.  Michael's  Mount  in 
Cornwall,  etc.,  afford  smaller  crystals.  The  physalite  va- 
riety occurs  in  crystals  of  immense  size  at  Finbo,  Sweden, 
in  a  granite  quarry,  and  at  Broddbo.  A  well-defined  crys- 
tal from  this  locality,  in  the  possession  of  the  College  of 
Mines  of  Stockholm,  weighs  eighty  pounds.  Altenberg  in 


288  DESCRIPTIONS   OF   MINERALS. 

Saxony,  is  the  principal  locality  of  pycnite.  It  is  there  as- 
sociated with  quartz  and  mica. 

Trumbull,  Conn.,  is  a  prominent  locality  of  this  species 
in  the  United  States.  It  seldom  affords  fine  transparent 
crystals,  except  of  a  small  size  ;  these  are  usually  white,  oc- 
casionally with  a  tinge  of  green  or  yellow.  The  large  coarse 
crystals  sometimes  attain  a  diameter  of  several  inches  (rare- 
ly six  or  seven),  but  they  are  deficient  in  lustre,  usually  of 
a  dull  yellow  color,  though  occasionally  white,  and  often 
are  nearly  opaque.  It  is  found  also  at  Crowder's  Mountain 
in  N.  0.  ;  in  Utah,  in  Thomas's  Mountains,  and  in  gold 
washings  in  Oregon. 

The  ancient  topazion  was  found  on  an  island  in  the  Red 
Sea,  which  was  often  surrounded  with  fog,  and  therefore 
difficult  to  find.  It  was  hence  named  from  topazo,  to  seek. 
This  name,  like  most  of  the  mineralogical  terms  of  the  an- 
cients, was  applied  to  several  distinct  species.  Pliny  describes 
a  statue  of  Arsinoe,  the  wife  of  Ptolemy  Philadelphus,  four 
cubits  high,  which  was  made  of  topazion,  or  topaz,  but  evi- 
dently not  the  topaz  of  the  present  day,  nor  chrysolite, 
which  has  been  supposed  to  be  the  ancient  topaz.  It  has 
been  conjectured  that  it  was  a  jasper  or  agate ;  others  have 
supposed  it  to  be  prase  or  chrysoprase. ' 

Topaz  is  employed  in  jewelry,  and  for  this  purpose  its 
color  is  often  altered  by  heat.  The  variety  from  Brazil  as- 
sumes a  pink  or  red  hue,  so  nearly  resembling  the  Balas 
ruby,  that  it  can  only  be  distinguished  by  the  facility  with 
which  it  becomes  electric  by  friction.  Beautiful  crystals 
for  the  lapidary  are  brought  from  Minas  Novas,  in  Brazil. 
"When  cut  with  facets  and  set  in  rings,  they  are  readily  mis- 
taken, if  viewed  by  daylight,  for  diamonds.  From  their 
peculiar  limpidity,  topaz  pebbles  are  sometimes  denomi- 
nated gouttes  d'eau. 

The  perfect  cleavage  of  topaz  makes  it  a  poor  substitute 
for  emery. 

Euclase. 

Monoclinic.  In  oblique  rhombic  prisms,  with  cleavage 
highly  perfect  parallel  to  the  clinodiagonal  section,  afford- 
ing smooth  polished  faces. 

Color  pale  green  to  white  or  colorless,  pale  blue.  Lustre 
vitreous;  transparent.  Brittle.  H.^7'5.  G.  =3'1.  Pyro- 
electric. 


SUBSILICATES.  289 

Composition.  H2Be2Al  0,0  Si2= Silica  41-20,  alumina  35 *^2, 
glucina  17-39,  water  6-19=  100.  B.B.  fuses  with  much  dif- 
ficulty to  a  white  enamel  ;  not  acted  on  by  acids. 

Diff.  The  cleavage  of  this  glassy  mineral  is,  like  that  of 
topaz,  very  perfect,  but  is  not  basal.  The  cleavage  distin- 
guishes it  from  tourmaline  and  beryl. 

Obs.   Occurs  in  the  Ural,  and  with  topaz  in  Brazil. 

The  crystals  of  this  mineral  are  elegant  gems  of  them- 
selves, but  they  are  seldom  cut  for  jewelry  on  account  of 
their  brittleness. 

Datolite.— Datholite.    Humboldtite. 

Monoclinic.  Crystals  without  distinct  cleavage  ;  small 
and  glassy.  Also  botryoidal, 
with  a  columnar  structure, 
and  then  called  botryolite. 
Color  white,  occasionally  gray- 
ish, greenish,  yellowish,  or  red- 
dish. Translucent.  H.= 5-5*5. 


Composition.  H2Ca2B2  010  Si« 
=  Silica  37*5,  boron  trioxide 
21-9,  lime  35 -0,  water  5  "6= 
100.  Botryolite  contains  twice 
the  proportion  of  water.  B.  B. 
becomes  opaque,  intumesces  and  melts  easily  to  a  glassy 
globule  coloring  the  flame  green.  Decomposed  by  hydro- 
chloric acid  ;  the  solution  gelatinizes  on  evaporation. 

Diff.  Its  glassy  complex  crystallizations,  without  cleavage, 
are  unlike  any  other  mineral  that  gelatinizes  with  acid. 
It  is  distinguished  from  minerals  that  it  resembles  also  by 
tingeing  the  blowpipe-flame  green. 

Obs.  Occurs  in  cavities  in  trap  rocks  and  gneiss.  Found 
in  Scotland  ;  at  Andreasburg ;  at  Baveno  ;  Toggiana ;  also 
Bergen  Hill,  in  N.  J. ;  in  Connecticut,  at  Eoaring  Brook, 
14  miles  from  New  Haven  ;  and  near  Hartford,  Berlin,  Mid- 
dlefield  Falls,  Conn. ;  also  in  great  abundance  at  Eagle 
Harbor  in  the  copper  region,  Lake  Superior,  and  on  Islo 
Royale  ;  also  near  Santa  Clara,  Cal. 

Homilite.  A  black  silicate  of  iron  and  calcium,  resembling  gadoli- 
nite,  but  affording  from  15  to  18  per  cent,  of  boracic  acid  with  32  of 
silica ;  formula  R8B2  O)0  Si2.  From  Brevig,  Norway. 


290  DESCRIPTIONS   OF   MINERALS. 

Titanite. — Sphene. 

Monoclinic.     In  very  oblique  rhombic  prisms  ;  the  lateral 
faces  making  angles  often  of  76°  7',  113°  31'  (/A/),  136°  12' 

1.  2. 


(2  A 2),  or  133°  52V  The  crystals  are  usually  thin  with 
sharp  edges.  Cleavage  in  one  direction  sometimes  perfect. 
Occasionally  massive.  •» 

Color  grayish-brown,  ash-gray,  brown  to  black;  some- 
times pale  yellow  to  green ;  streak  uncolored.  Lustre 
adamantine  to  resinous.  Transparent  to  opaque.  H.  =  5- 
5-5.  G. =3 '2-3 -6. 

Composition.  CaTi05  Si  =  Silica  30-6,  titanium  dioxide 
40 '82,  lime  28'57  — 100  ;  in  dark  brown  and  black  crystals, 
some  iron  replaces  part  of  the  calcium.  B.B.  fuses  with 
intumescence.  Imperfectly  decomposed  by  hydrochloric 
acid. 

The  dark  varieties  of  this  species  were  formerly  called 
titanite,  and  the  lighter  sphene.  The  name  sphene  alludes 
to  the  wedge-shaped  crystals,  and  is  from  the  Greek  sphen, 
wedge.  Greenovite  is  a  variety  colored  rose-red  by  manga- 
nese. 

Dtff.  The  thin  wedge-like  form  of  the  crystals,  in  general, 
readily  distinguish  this  species ;  but  some  crystals  are  very 
complex. 

Obs.  Sphene  occurs  mostly  in  disseminated  crystals  in 

franite,  gneiss,  mica  slate,  syenyte,  or  granular  limestone, 
t  is  usually  associated  with  pyroxene  and  scapolite,  and 
often  with  graphite.     It  has  been  found  in  volcanic  rocks. 
The  crystals  are  commonly  J  to  J  an  inch  long ;  but  are 
eometimes  2  or  more  inches  in  length. 

Foreign  localities  are  Arendal  in  Norway  ;  at  St.  Gothard 
and  Mont  Blanc  ;  in  Argyleshire  and  Galloway  in  Great 
Britain.  Occurs  in  Canada,  at  Grenville  and  elsewhere ; 
New  York,  at  Roger's  Rock,  on  Lake  George  ;  with  graphite 


SUBSILICATES.  291 

and  pyroxene,  at  Gouverneur,  near  Natural  Bridge  in  Lewis 
County  (the  variety  called  Lederite);  in  Orange  County  in 
Monroe,  Edenville,  Warwick,  and  Amity  ;  near  Peekskill  in 
Westchester  County,  and  near  West  Farms  ;  in  Massachu- 
setts, at  Lee,  Bolton,  and  Pelham  ;  in  Connecticut,  at  Trum- 
bull ;  in  Maine,  at  Sanford,  and  Thomaston  ;  in  New  Jer- 
sey, at  Franklin  ;  in  Pennsylvania,  near  Attleboro',  Bucks 
County  ;  in  Delaware,  at  Dixon's  quarry,  7  miles  from 
Wilmington ;  in  Maryland,  25  miles  from  Baltimore,  on 
the  Gunpowder. 

Ouarinite.    Like  sphene  in  composition,  but  trimetric. 

Keilhauite,  or  Tttro-titanite.  Related  to  sphene.  Brownish-black, 
with  a  grayish-brown  powder.  G.  =3*69.  H.  =6*5.  Fuses  easily. 
Affords  Silica  30  '0,  titanic  acid  29  0,  yttria  9' 6,  lime  18 '9,  iron  sesqui- 
oxide  6*4,  alumina  6*1.  From  Arendal,  Norway. 

Tscheffkinite.  Near  Keilhauite.    From  the  llmen  Mountains. 
« 

Staurolite. — Staurotide. 

Trimetric.    /A  7=129°  20'.    Cleavage  imperfect.    Usual- 
ly in  cruciform  twin   crystals.     Fig-  2. 
ure   2    is  a  common  kind  ;    another 
crosses  at  an  acute   angle  near   60°  ; 
and  another,  of  rare  occurrence,  con- 
sists of  three  crystals  intersecting  at 
angles   near   60°.     Never  in  massive 
forms  or  slender  crystallizations. 
Color  dark  brown  or  black.     Lustre  vitreous,  inclining 
to  resinous  ;  sometimes  bright,  but  often   dull.     Translu- 
cent to  opaque.     H.=7-7'5.     G.=3'4-3'8. 

Composition.  H2R3A16  O34  Si6= Silica  30*37,  alumina  51*92, 
iron  protoxide  13'66,  magnesia  2-53,  water  1*52=100.  B.B. 
infusible.  Insoluble  in  acids. 

Diff.  Distinguished  from  tourmaline  and  garnet  by  its 
infusibility  and  form. 

Obs.  Found  in  mica  slate  and  gneiss,  in  imbedded  crys- 
tals. 

Occurs  very  abundant  through  the  mica  schist  of  New 
England  :  Franconia,  Vt. ;  Windham,  Me. ;  Lisbon,  N.  H. ; 
Chesterfield,  Mass  ;  Bolton  and  Tolland,  Ct.  ;  also  on  the 
Wichichon,  eight  miles  from  Philadelphia  ;  at  Canton,  and 
in  Fannin  County,  Georgia.  Mt.  Campione  in  Switzerland, 
and  the  Greiner  Mountain,  Tyrol,  are  noted  foreign  locali- 
ties. 


DESCRIPTIONS   OF  MINERALS. 

The  name  staurolite  is  from  the  Greek  stauros,  a  cross. 

Schorlomite.  Black,  and  often  irised  tarnished.  Streak  grayish-black. 
H.  =7-7 '5.  G.  =380.  Fuses  readily  on  charcoal.  Easily  d'ecomposed 
by  the  acids,  and  gelatinizes.  Contains  much  titanium,  with  iron,  lime, 
and  silica.  From  Magnet  Cove,  Arkansas,  and  Kaiserstuhlgebirge, 
Breisgau. 


B.  HYDROUS  SILICATES. 

The  three  sections  under  which  the  Hydrous  Silicates 
are  arranged  are  the  following  : 

I.  GENERAL  SECTION.     Under  this  section  there  are  in- 
cluded :   (1)  Bisilicates — Pectolite,    Laumontite,  Apophy- 
lite,  etc.  ;  (2)  Unisilicates — Prehnite,  Calamine,  etc.  ;  and 
(3)  Subsilicates — as  Allophane,  and  some  related  species. 

II.  ZEOLITE  SECTION.     The  minerals  included  are  feld- 
spar-like in  constituents,  and  apparently  so  in  quantivalent 
(or  oxygen)  ratio  ;  the  basic  elements  being,  as  in  the  feld- 
spars, (1)  aluminum,  and  (2)  the  metals  of  the  alkalis  K, 
Na,  and  of  the  alkaline  earths  Ca,  Ba,  with  also  Sr,  to  the 
almost  total  exclusion  of  magnesium  and  iron. 

III.  MARGAROPHYLLITE    SECTION.      This  section   em- 
braces species    having  a  micaceous  or  thin-foliated  struc- 
ture when  crystallized,  with  the  surface  of  the  folia  pearly, 
and  the  plane  angle  of  the  base  of  the  prism  120°.    Whether 
crystallized   or  massive   the  feel  is  greasy,  at  least  when 
pulverized.  It  comprises  (1)  Bisilicates  :  including  Talc  and 
Pyrophyllite,  which  are  atomically  and  physically  similar 
species,  although  the  former  is  a  magnesium  silicate,  and 
the   latter   an   aluminum   silicate  ;   (2)  Non-alkaline  Uni- 
silicates, including  Kaolinite  and  Serpentine,  which  have  a 
similar  difference  in   constituents  to  the  preceding  with 
the  same  likeness  in  composition,  and  also  some  related 
species  ;  (3)  Alkaline  Unisilicates  :  as,  Finite  and  the  Hy- 
drous Micas,  which  are   species   containing  potassium    or 
sodium  as  an  essential  constituent;  (4)  the  Chlorite  Group, 
the  species  of  which  arc  mostly  Subsilicates. 


HYDROUS   SILICATES — GENERAL   SECTION.  293 

I.   GENERAL  SECTION, 
Pectolite. 

Monoclinic,  isomorphous  with  wollastonite.  Usually  in 
aggregations  of  acicular  crystals,  or  fibrous-massive,  radiate, 
stellate.  Color  white,  or  grayish.  Translucent  to  opaque. 
Tough.  H.=5.  G. =2-68-2 -8. 

Composition.  R  03  Si,  in  which  R=r£H2  -J-Na2  fCa,  =  Silica 
54-2,  lime  33*8,  soda  9-3,  water  2'7=100.  In  the  closed 
tube  yields  water.  B.  B.  easily  fusible.  Decomposed  by  hydro- 
chloric acid,  and  the  solution  gelatinizes  somewhat  when 
evaporated. 

i>iff.  Its  fibrous  forms  and  its  blowpipe  reactions  are 
distinctive. 

Obs.  Occurs  mostly  in  cavities  or  seams  in  trap  or  basic 
eruptive  rocks,  and  occasionally  in  other  rocks.  Found 
at  Ratho  Quarry,  near  Edinburgh,  Scotland ;  at  Kilsyth  ; 
Isle  of  Skye  ;  in  the  Tyrol  ;  in  fine  specimens  at  Bergen 
Hill,  N.  J. ;  a  compact  variety  at  Isle  Royale,  Lake  Supe- 
rior. 

Okenite  and  Gyrolite  are  related  hydrous  calcium  silicates.  Okenite 
is  from  the  Faroe  Islands,  Iceland,  and  Greenland,  and  gyrolite  from 
the  Isle  of  Skye,  and  from  Nova  Scotia  25  miles  southwest  of  Cape 
Blomidon. 

Liaumontite. 

Monoclinic,  with  the  angles  nearly  of  pyroxene  ;  /A  /= 
86°  16'.  Cleavage  parallel  to  the  clinodiagonal  section  and 
to  /  perfect.  Also  massive,  with  a  radiating  or  divergent 
structure. 

Color  white,  passing  into  yellow  or  gray,  sometimes  red. 
Lustre  vitreous,  inclining  to  pearly  on  the  cleavage  face. 
Transparent  to  translucent.  H.  =  3'5-4.  G.=2'25-2'36. 
Becomes  opaque  on  exposure  through  loss  of  water,  and 
readily  crumbles. 

Composition.  CaAl  0,5Si4  +  4 aq= Silica  50'0,  alumina 
21-8,  lime  11-9,  water  16-3  =  100.  B.B.  swells  up  and  fuses 
easily  to  a  white  enamel.  Decomposed  by  hydrochloric  acid, 
and  the  solution  gelatinizes  on  evaporation. 

Diff.  The  alteration  this  species  undergoes  on  exposure 
to  the  air  at  once  distinguishes  it.  This  result  may  be 
prevented  with  cabinet  specimens,  by  dipping  them  into  a 
solution  of  gum  arabic. 


294 


DESCRIPTIONS   OF  MINERALS. 


Otis.  Found  in  the  veins  and  cavities  of  trap  rocks  and 
also  in  gneiss,  porphyry.  Occurs  at  the  Faroe  Islands  ;  Kil- 
patrick  Hills,  near  Glasgow ;  Disco,  Greenland  ;  St.  Groth- 
ard,  Switzerland  ;  Peter's  Point,  Nova  Scotia  ;  Phippsburg, 
Me.;  Charlestown  syenite  quarries,  Mass.  ;  Bergen  Hill, 
N.  J. ;  the  Copper  region,  Lake  Superior,  and  Isle  Royale. 

Leonhardite.  Probably  Laumontite  which  has  lost  part  of  its  water 
by  alteration.  It  resembles  that  species  in  crystallization  and  in  most 
of  \ts  characters,  but  differs  in  being  less  efflorescent  on  exposure  to  a 
dry  atmosphere.  Analyses  of  specimens  from  Copper  Falls,  Lake 
Superior,  have  obtained,  Silica  55'50,  alumina  2.1  '19,  lime  10'5G,  water 
11*93  =  99-68.  The  Copper  Falls  variety  alters  little  on  exposure. 
Reported  also  from  trachyte  at  Schemnitz,  in  Hungary,  and  from  Pfitsch 
in  the  Tyrol 

Apophyfflte. 

Dimetric.  In  square  octahedrons,  prisms,  and  tables. 
Cleavage  parallel  with  the  base  highly  perfect.  Massive 


1. 


3. 


and  foliated.  Color  white  or  grayish  ;  sometimes  with  a 
shade  of  green,  yellow,  or  red.  Lustre  of  O  pearly  :  of  the 
other  faces  vitreous.  Transparent  to  opaque.  H.=4*5— 5. 
G.  =2  -3-2-4. 

Composition.  A  silicate  of  calcium  and  hydrogen  com- 
bined, with  potassium  fluoride  and  water,  of  the  formula 
(JH2£Ca)  03Si  +  £KF+iaq  =  Silica  52'97,  lime  24-^2, 
potash  5-20,  water  15 '90,  fluorine  2-10=100-89.  B.B.  exfo- 
liates, colors  the  flame  violet  (owing  to  the  potash),  and 
fuses  very  easily  to  a  white  enamel.  In  the  closed  tube 
yields  water  which  has  an  acid  reaction.  Decomposed  by 
hydrochloric  acid  with  the  separation  of  slimy  silica. 


HYDROUS   SILICATES — GENERAL   SECTION.  295 

Diff.  The  pearly  basal  cleavage  and  the  forms  of  its  glassy 
crystals  at  once  distinguish  it  from  the  preceding  species. 
The  prisms  are  sometimes  almost  cubes,  with  the  angles 
cut  oif  by  the  planes  of  the  pyramid  ;  but  the  difference  in 
the  lustre  of  the  prismatic  and  basal  faces  shows  that  it 
is  dimetric. 

The  name  alludes  to  its  exfoliation  before  the  blowpipe. 

Obs.  Found  in  amygdaloidal  trap  and  basalt. 

Occurs  in  fine  crystallizations  at  Peter's  Point  and  Par- 
tridge Island,  Nova  Scotia,  at  Bergen  Hill,  N.  J.,  the  Cliff 
Mine,  Lake  Superior  region. 

Catapleiite.  A  hydrous  zirconium  and  sodium  silicate,  from  Nor- 
way. 

Dioptase  and  Chrysocolla.     Hydrous  copper  silicates.    See  p.  141. 

Picrosmine,  Pyrallolite,  Picropliyll,  Traversellite,  Pitkaraiulite,  Stra- 
konitzite,  Monradite,  are  names  of  varieties  of  pyroxene  in  different 
stages  of  alteration.  Xylotine  is  probably  altered  asbestus. 

Frehnite. 

Trimetric.  /A  7=99°  56'.  Cleavage  basal.  Sometimes 
in  six-sided  prisms,  rounded  so  as  to  be  barrel-shaped,  and 
composed  of  a  series  of  united  plates  ;  also  in  thin  rhom- 
bic or  hexagonal  plates.  Usually  reniform  and  botryoidal, 
with  a  crystalline  surface  ;  texture  compact. 

Color  light  green  to  colorless.  Lustre  vitreous,  except 
the  face  0,  which  is  somewhat  pearly.  Subtransparent  to 
translucent.  H.  =  6-6-5.  G.  =2-8-2 '96. 

Composition.  H2Ca2A10i2  Si3= Silica  43-6,  alumina  24*9, 
lime  27'1,  water  4-4=100.  B.B.  fuses  very  easily  to  an  en- 
amel-like glass.  Decomposed  by  hydrochloric  acid,  leaving 
a  residue  of  silica  in  light  flakes,  but  the  solution  does  not 
gelatinize.  Yields  a  little  water  when  heated  in  a  closed 
tube. 

Diff.  Distinguished  from  beryl,  green  quartz,  and  chal- 
cedony by  fusing  before  the  blowpipe,  and  from  the  zeolites 
by  its  superior  hardness. 

Obs.  Found  in  the  cavities  of  trap,  gneiss,  and  granite. 

Occurs  in  the  trap  rocks  of  the  Connecticut  Valley,  and 
at  Paterson  and  Bergen  Hill,  N.  J.  ;  in  gneiss  at  Bellows 
Falls,  Vt.  ;  in  syenyte  at  Charlestown,  Mass. ;  and  very 
abundant,  forming  large  veins,  in  the  Copper  region  of  Lake 
Superior,  three  miles  south  of  Cat  Harbor,  and  elsewhere. 

The  Fassa  Valley  in  the  Tyrol,  St.  Christophe  in  Dau- 


296  DESCRIPTIONS   OP   MINERALS. 

phiny,  and  the  Salisbury  Crag,  near  Edinburgh,  are  some 
of  the  foreign  localities. 

Prehnite  receives  a  handsome  polish  and  is  sometimes 
used  for  inlaid  work.  In  China  it  is  polished  for  orna- 
ments, and  large  slabs  have  been  cut  from  masses  brought 
from  there. 

Clilorastrolitc  and  Zonochlorite,  from  the  Lake  Superior  region,  are 
impure  prehnite. 

Chalcomorphite.  A  hydrous  calcium  silicate,  from  calcite  in  cavities 
of  lava,  containing  but  25  "4  per  cent,  of  silica. 

Gismondite  (Zeagonite).  A  hydrous  lime-aluminum  silicate,  occur- 
ring in  trimetric  crystals  resembling  square  octahedrons  ;  found  in 
lava  at  Capo  di  Bove,  near  Rome. 

Edingtonite.  A  hydrous  barium-aluminum  silicate.  Occurring  in 
crystals  and  massive.  From  the  Kilpatrick  Hills,  with  harmotome. 

Carpholite.  A  manganese- aluminum  silicate,  occurring  in  silky, 
yellow,  radiated  tufts.  From  the  tin  mines  of  Schlackenwald. 

PyrosmaMte.  A  manganese-iron  silicate  and  chloride,  from  Sweden. 

Goldmine.     A  hydrous  zinc  unisilicate.     See  p.  157. 

Villarsite.     Probably  altered  chrysolite. 

Cerite,  Tritomite,  Erdmannite,  are  cerium  and  lanthanum  silicates. 

Thorite  (Orangite)  and  JSucrasite,  are  thorium  silicates ;  the  latter 
hydrous. 

Allophane. 

In  amorphous  incrustations,  with  a  smooth  small-mam- 
millary  surface,  and  often  hyalite-like,  and  sometimes  pul- 
verulent. Color  pale  bluish-white  to  greenish-white,  and 
deep  green ;  also  brown,  yellow,  colorless.  Translucent. 
H.=3.  G.=  1-85-1-89. 

Composition.  Mostly  Al  05  Si  +  6  (or  5)  aq.  Silica  23-75, 
alumina  40*6^,  water  35-63  =  100.  In  the  closed  tube  yields 
much  water.  B.B.  infusible,  but  crumbles.  A  blue  color 
with  cobalt  solution,  and  a  jelly  with  hydrochloric  acid. 

Occurs  in  Saxony  ;  at  the  Chessy  Copper  Mine  near 
Lyons  ;  at  a  copper  mine  in  Bohemia  ;  with  limonite  in 
Moravia  ;  in  Old  Chalk  Pits  near  Woolwich,  England  ;  with 
gibbsite  in  limonite  beds  in  Richmond,  Mass. ;  at  the  cop- 
per mine  of  Bristol,  Conn.;  at  Morgantown,  Pa.;  copper 
mines  of  Polk  County,  Tenn. 

Collyrite.  A  hydrous  aluminum  silicate  containing  only  14  to  15  per 
cent,  of  silica,  and  35  to  40  of  water  ;  and  Schrotterite  is  another  with 
11  to  12  per  cent,  of  silica.  The  latter  has  been  reported  as  occurring, 
as  a  gum-like  incrustation,  at  the  falls  of  Little  River,  on  Sand  Moun- 
tain, Cherokee  Counfy,  Alabama.  Scarbroite  is  a  related  mineral 
of  doubtful  nature. 


HYDROUS   SILICATES — ZEOLITE   SECTION.  297 

II.  ZEOLITE  SECTION. 

The  species  of  the  Zeolite  Section  have  beer/  described  as 
having  some  relation  to  the  feldspars  in  constitution.  In 
the  feldspars,  as  explained  on  page  273,  the  following  ratios, 
for  the  protoxides,  alumina,  and  silica  which  analyses  af- 
ford, occur:  1:3:4,1:3:6,1:3:8,1:3:9,1:3:10,  1:3:12. 
So,  among  the  zeolites,  if  the  water  be  left  out  of  considera- 
tion, these  are  the  ratios:  1:3:4  (in  Thomsonite),  1:3:6 
(Natrolite,  Scolecite,  etc.),  1:3:8  (Analcite,  Chabazite, 
etc.),  1:3:10  (Harmotome),  1:3: 12  (Stilbite,  Heulandite, 
etc.).  This  fact,  added  to  the  absence  or  nearly  total  ab- 
sence of  magnesium  and  iron,  and  presence  instead  of  Na2, 
K2,  Ca,  Ba,  make  out  a  distinct  relation  to  the  feldspars, 
whatever  may  be  the  part  which  the  water  sustains  in  the 
compounds.  Besides  barium,  strontium  is  sometimes  pres- 
ent, an  element  not  yet  known  to  characterize  a  species  of 
feldspar. 

These  minerals  were  called  zeolites  because  they  generally 
fuse  easily  with  intumescence  before  the  blowpipe,  the  term 
being  derived  from  the  Greek  zeo,  to  boil.  Among  those 
described  beyond,  Heulandite  and  Stilbite,  have  a  strong 
pearly  cleavage,  and  the  latter  is  often  in  pearly  radiations ; 
Natrolite,  Scolecite,  are  fibrous  and  radiated,  or  in  very 
slender  prisms  ;  Thomsonite  occurs  either  radiated,  or  com- 
pact, or  in  short  crystals  ;  while  Harmotome,  Analcite,  and 
Chabazite,  and  the  related  Gmelinite,  occur  only  in  short 
or  stout  glassy  crystals,  those  of  chabazite  looking  some- 
times like  cubes. 

The  zeolites  are  sometimes  called  trap  minerals,  because 
they  are  often  found  in  the  cavities  or  fissures  of  amygda- 
loidal  trap  as  well  as  related  basic  eruptive  rocks.  Yet 
they  occur  also  occasionally  in  fissures  or  cavities  in  gneiss, 
granite,  and  other  metamorphic  rocks.  They  are  not  the 
original  minerals  of  any  of  these  rocks  ;  but  the  results  of 
alteration  of  portions  of  them  near  the  little  cavities  or  fis- 


298  DESCRIPTIONS   OP   MINERALS. 

sures  in  which  the  minerals  occur  ;  and  part  were  made 
while  the  rock  was  still  hot,  and  as  cooling  went  forward. 
Besides  true  zeolites,  such  cavities  often  contain  also 
Laumontite  (p.  293),  noted  for  its  tendency  to  crumble 
on  exposure ;  Pectolite  and  Okenite  (p.  293),  which  are 
fibrous  like  Natrolite  and  Scolecite  ;  Apophyllite  (p.  294), 
having  one  pearly  cleavage  like  heulandite  and  stilbite ; 
Prehnite  (p.  295),  usually  apple-green  ;  Datolite  (p.  289), 
in  stoutish  glassy  complex  crystals,  or  in  smooth  botryoidal 
forms  ;  Aragonite  (p.  218),  sometimes  radiated  fibrous,  and 
Calcite  (p.  215)  with  its  three  directions  of  like  easy  cleav- 
age, both  effervescing  with  hydrochloric  acid  ;  Siderite 
(p.  185),  in  spheroidal  or  other  forms  ;  Chlorite  (p.  316), 
of  dark  olive-green  color  ;  and  Quartz,  either  in  crystals, 
or  as  chalcedony,  agate,  or  carnelian,  and  in  either  case 
easily  distinguished  by  the  hardness,  absence  of  cleavage, 
and  infusibility.  Of  all  these  species  Calcite  and  Quartz 
are  the  most  common.  Of  rarer  occurrence  than  the  above, 
there  are  Orthoclase,  Asphaltic  coal,  Copper,  etc. 

All  the  zeolites  yield  water  in  the  closed  tube,  and  many 
of  them  gelatinize  with  hydrochloric  acid. 

Thomsonite. 

Trimetric.  In  right  rectangular  prisms.  Usually  in 
masses  having  a  radiated  structure  within,  and  consisting 
of  long  fibres,  or  acicular  crystals  ;  also  amorphous. 

Color  snow-white  ;  impure  varieties  brown.  Lustre  vi- 
treous, inclining  to  pearly.  Transparent  to  translucent. 
H.=5-5.  Brittle.  G.  =2-3-2-4. 

Composition.  (Ca,Na2)Al  08  Si, +.2 Jaq= Silica  38-09,  al- 
umina 31-62,  lime  12-60,  soda  4-62,  water  13 "40  =100 '20. 

B.  B.  fuses  very  easily  to  a  white  enamel.  Decomposed  by 
hydrochloric  acid:  the  solution  gelatinizes  when  evaporated. 
' Diff.  Distinguished  from  natrolite  by  its  fusion  to  an 
opaque  and  not  to  a  glassy  globule. 

Obs.  Occurs  in  amygdaloid,  near  Kilpatrick,  Scotland  ; 
in  lavas  at  Vesuvius,  Comptonite;  in  clinkstone  in  Bohemia; 
the  Tyrol,  etc. ;  at  Peter's  Point,  Nova  Scotia,  in  trap ;  a 
massive  variety,  called  Ozarkite,  at  Magnet  Cove,  Ark. 


HYDROUS    SILICATES — ZEOLITE   SECTION. 


The  species  was  named  after  Dr.  Thomas  Thomson,  of 
Glasgow. 

Natrolite. 

Trimetric.  In  slender  prisms,  terminated  by  a  short  pyra 
mid;  /A/=91°;  1  Ai  over a?=U3°  20'.  Also 
in  globular,  stellated,  and  divergent  groups, 
consisting  of  delicate  acicular  fibres,  the 
fibres  often  terminating  in  acicular  prismatic 
crystals. 

Color  white,  or  inclining  to  yellow,  gray, 
or  red.  Lustre  vitreous.  Transparent  to 
translucent.  H.  =  5-5'5.  G.  =  2  -1 7-2  -25. 
Brittle. 

Composition.  NagAl  0,0  Si3  +  2  aq  =  Silica 
47'29,    alumina    26*06,    soda   16*30,    water 
9 '45  =  100.     B.B.  fuses  easily  and  quietly  to  a  clear  glass  ; 
a  fine  splinter  melts  in  a  candle  flame.     Decomposed  by  hy- 
drochloric acid,  and  the  solution  gelatinizes  on  evaporation. 

Diff.  Distinguished  from  scolecite  by  its  quiet  fusion. 

Obs.  Found  in  amygdaloidal  trap,  basalt  and  volcanic 
rocks;  sometimes  in  seams  in  granitic  rocks.  The  name 
natrolite  is  from  natron,  soda. 

Occurs  in  Bohemia;  Auvergne;  Fassathal,  Tyrol;  at  Glen 
Farg  in  Fifeshire ;  in  Dumbartonshire  ;  Nova  Scotia  ;  Ber- 
gen Hill,  N.  J. 

Scolecite.  Resembles  natrolite,  and  differs  in  containing  lime  in  place 
of  soda ;  also  in  having  its  slender  rhombic  glassy  prisms  longitudi- 
nally twinned,  as  is  shown  by  the  meeting  of  two  ranges  of  striae  at  an 
angle  along  or  near  the  central  line  of  opposite  prismatic  planes.  The 
lustre  is  vitreous  or  a  little  pearly.  B.B.  it  curls  up  like  a  worm 
(whence  the  name  from  the  Greek  skolex,  a  worm)  and  then  melts. 
From  Staffa,  Iceland,  Finland,  Hindostan. 

Mesolite.   Another  related  species. 

Analcite. 

Dimetric  or  Trimetric.    Occurs  usually  in  trapezohedron 

(fig.  1,  also  fig.  2). 

The  appearance  sometimes 
seen  in  polarized  light  is 
shown  in  figure  7,  page  69 
On  account  of  this  peculiar 
behavior  and  indications  of 
a  compound  structure  ob- 
tained in  a  microscopic  study 


1. 


300  DESCRIPTIONS   OF   MINERALS. 

of  thin  slices,  it  has  been  suspected  to  be  dimetric  like 
leucite,  or  else  t  rime  trie  like  phillipsite,  although  the  forms 
of  the  crystals  are  apparently  isometric.  Often  colorless 
and  transparent,  also  milk-white,  grayish  and  reddish- 
white,  and  sometimes  opaque.  Lustre  vitreous.  H.  =5-5 '5. 
G.=2  25. 

Composition.  Na2Al  Oi2Si4 4-  2aq  =  Silica  54*47,  alumina 
23-29,  soda  14-07,  water  8-17  =  100.  B.B.  fuses  easily  to  a 
colorless  glass.  Decomposed  by  hydrochloric  acid  ;  and  the 
silica  separates  in  gelatinous  lumps. 

Diff.  Characterized  by  its  crystallization,  without  cleav- 
age. Distinguished  from  quartz  and  leucite  by  giving  water 
in  a  closed  glass  tube  ;  from  calcite  by  its  fusibility,  and  by 
not  effervescing  with  acids  ;  from  chabazite  and  its  varieties 
by  fusing  without  intumescence  to  a  glassy  globule,  and  by 
the  crystalline  form. 

Obs.  Found  in  cavities  and  seams  in  amygdaloid'al  trap, 
basalt  and  other  eruptive  rocks,  and  sometimes  in  granite, 
syenyte  and  gneiss. 

Occurs  in  fine  crystallizations  in  Nova  Scotia ;  also  at 
Bergen  Hill,  N.  J. ;  Ferry,  Me. ;  and  in  the  trap  of  the  Cop- 
per region,  Lake  Superior.  The  Faroe  Islands,  Iceland  ; 
Glen  Farg,  near  Edinburgh ;  Kilmalcolm,  the  Campsie 
Hills,  and  Antrim  ;  the  Vicentine  ;  the  Hartz  at  Andreas- 
berg  ;  Sicily,  and  Vesuvius,  are  some  of  the  foreign  localities. 

The  name  analcite  is  from  the  Greek,  analkis,  weak,  al- 
luding to  its  weak  electric  power  when  heated  or  rubbed. 

EudnopMte.     Near  analcite.    From  Norway. 

Faujasite.     In  isometric  octahedrons.  From  the  Kaiserstuhl,  Baden. 

Chabazite. 

Rhombohedral.  Often  in  rhombohedrons,  much  resem- 
bling cubes.  R  :  72=94°  46'.  Cleavage  parallel  to 
R.  Also  in  complex  modifications  of  this  form. 
Never  massive  or  fibrous. 

Color  white,  also  yellowish,  and  flesh-red  or  red. 
Lustre  vitreous.     Transparent  to  translucent.    H.  — 
4-5.     G.  =2-08-3-19. 

The  red  chabazite  of  Nova  Scotia  has  been  called  Acadi- 
alite. 

Composition.  CuAl  0,2  Si4-f  6aq,  with  a  little  Na2  or  K2  in 
place  of  part  of  the  Ca.  The  Nova  Scotia  acadialite  afforded 


HYDROUS   SILICATES — ZEOLITE   SECTION.  301 

Silica  52*20,  alumina  18*27,  lime  6 '58,  soda  and  potash  2*12, 
water  20-52.  B.  B.  intumesces  and  fuses  to  a  nearly  opaque 
bead.  Decomposed  by  hydrochloric  acid,  with  the  separa- 
tion of  slimy  silica.  In  the  closed  tube  gives  water.  Phac- 
olite  is  a  variety  in  complex  glassy  crystals. 

Diff.  The  nearly  cubical  form  often  presented  by  the 
crystals  of  chabazite  is  a  striking  character.  It  is  distin- 
guished from  analcite  as  stated  under  that  species  ;  from 
calcite  by  its  hardness  and  action  with  acids  ;  from  fluorite 
by  its  form  and  cleavage,  and  its  showing  no  phosphores- 
cence. 

Obs.  Found  in  trap  and  occasionally  in  gneiss,  syenyte, 
and  other  rocks.  Chabazite  is  met  with  in  the  trap  of  Con- 
necticut Valley,  but  in  poor  specimens  ;  also  at  Hadlyme 
and  Stonington,  Conn.;  Charlestown,  Mass.;  Bergen  Hill, 
N.  J. ;  Piermont,  N.  Y.;  Jones's  Falls,  near  Baltimore 
(Haydenite).  Nova  Scotia  affords  common  chabazite,  and 
also  the  acadialite  in  abundance.  The  Faroe  Islands,  Ice- 
land, and  Giant's  Causeway,  are  some  of  the  foreign  locali- 
ties ;  also  the  County  of  Antrim,  Ireland. 

Herschdite.     Near  chabazite,  if  not  identical  with  it.     From  Sicily. 

Omelinite.  Closely  resembles  some  chabazite,  but  its  crystals  are 
usually  hexagonal  rather  than  rhombohedral  in  appearance.  Formula 
(Na2,Ca)Al2  O,2  Si4.  A  Bergen  Hill  specimen  afforded  Silica  48  67,  alu- 
mina 18'72,  lime  2 -60,  soda  9 '14,  water  21  -35 =100 '48.  Gelatinizes  with 
hydrochloric  acid,  but  in  other  respects  resembles  chabazite.  Occurs 
at  Andreasberg ;  in  Antrim,  Ireland  ;  in  Skye  ;  at  Bergen  Hill,  N.  J.  ; 
in  Nova  Scotia  at  Cape  Blomidon.  Named  after  the  chemist,  Gmelin. 

Levynite  (Let>yne\     Rhombohedral,  and  somewhat  resembling  gme- 

nite  in  its  crystals  ;  excluding  the  water,  having  the  quantivalent 
itio  of  labradorite,  1:3:6.  Colorless,  white,  grayish,  reddish.  From 

eland,  Greenland,  Antrim,  Londonderry,  Hartfield  Moss  near  Glas- 

>w.     Named  after  the  crystallographer,  Levy. 

Harmotome. 

Monoclinic.  Unknown  except  in  compound  crystals;  and 
commonly  in  forms  similar  to  the  annexed  figure  ;  also  in 
compound  rhombic  prisms. 

Color  white  ;  sometimes  gray,  yellow,  red,  or  brownish. 
Subtransparent  to  translucent.  Lustre  vitreous.  H.  =  4'5. 
Cr.  =  2-45. 

Composition.  BaAl  014Si5  +  5  aq  =  Silica  46 *5,  alumina  1 5 '9, 
baryta  23 '7,  water  13 -9  =  100  ;  but  a  little  of  the  baryta  re- 
placed by  potash.  B.B.  whitens,  crumbles,  and  fuses  quietly 


302 


DESCRIPTIONS  OP  MINERALS. 


to  a  white  translucent  glass.  Gives  water  in  a  closed  glass 
tube.  Partially  decomposed  by  hydrochloric  acid,  and  if 
sulphuric  acid  be  added  to  the  solution, 
a  heavy  white  precipitate  of  barium  sul- 
phate is  formed.  Some  varieties  phos- 
phoresce when  heated. 

Diff.  Its  twin  crystals,  when  distinct, 
cannot  be  mistaken  for  any  other  species 
except  phillipsite.  Much  more  fusible 
than  glassy  feldspar  or  scapolite ;  does 
not  gelatinize  in  acids  like  thomsonite. 

Ofa.  Occurs  in  amygdaloidal  trap, 
and  in  trachyte  and  phonolyte,  also  in 
gneiss,  and  metalliferous  veins.  Fine 
crystallizations  are  found  at  Strontian  in  Scotland,  and 
in  Dumbartonshire  ;  Andreasberg  in  the  Hartz  ;  Kongs- 
berg  in  Norway.  Has  been  found  in  seams  in  the  gneiss 
of  the  upper  part  of  New  York  Island. 

The  name  harmotome  is  from  the  Greek  Jiarmos,  a  joint, 
and  temno,  to  cleave. 

Phillipsite.  Near  harmotome  in  its  cruciform  crystals  and 
other  characters  ;  but  differing  in  containing  lime  in  place 
of  baryta.  It  differs  also  in  gelatinizing  with  acids  and  in 
fusing  with  some  intumescence.  It  also  occurs  in  sheaf -like 
aggregations  and  in  radiated  crystallizations.  From  the 
Giant's  Causeway,  Capo  di  Bove,  Vesuvius,  Sicily,  Iceland. 

Epistttbite.  A  hydrous  silicate  of  alumina  and  lime.  Occurs  in 
thin  rhombic  prisms,  of  a  white  color,  with  a  perfect  pearly  cleavage 
like  stilbite.'  H.=4-4'5.  G.=:2'2o.  Before  the  blowpipe  froths  and 
forms  a  vesicular  enamel.  Does  not  gelatinize.  From  Iceland  and 
Hindostan,  and  sparingly  at  Bergen  Hill,  N.  J. 

Bravaisite.  Supposed  to  be  a  zeolite  ;  it  has  potassium,  magnesium 
and  iron  as  the  protoxide  bases. 

Stilbite. 

In  pyramidally  terminated  rectangular  prisms  usually 
flattened  parallel  to  the  face  i~i,  which  is  the 
direction  of  cleavage  and  is  very  pearly  in  lustre. 
1A1  =  119°  16',  and  114°.  Also  in  sheaf-like  ag- 
gregations, and  thin  lamellar  and  columnar  ;  also 
in  pearly  radiated  crystallizations. 

Color  white  ;  sometimes  yellow,  brown  or  red. 
Subtransparent  to  translucent.  H.= 3*5-4.  G.= 
2  -1-2  -15. 


HYDROUS   SILICATES — SEOLITE   SECTION.  303 

Composition.  CaAl  016  Si6  +  6  aq  =  Silica  57*4,  alumina  16*5, 
lime  8-9,  water  17*2=:  100;  but  with  a  little  Na2or  K2in 
place  of  part  of  the  Ca.  B.B.  exfoliates,  swells  up,  and 
curves  into  fan-like  forms,  and  fuses  to  a  white  enamel. 
Decomposed  by  hydrochloric  acid  without  gelatinizing. 

Diff.  It  cannot  be  scratched  with  the  thumb-nail,  like 
gypsum.  It  is  distinguished  from  heulandite  by  its  crys- 
tals. 

Obs.  Occurs  mostly  in  trap-rocks  ;  also  on  gneiss  and 
granite.  Found  on  the  Faroe  Ids. ;  Isle  of  Skye  ;  Isle  of  Ar- 
ran,  and  elsewhere,  Scotland  ;  Andreasberg,  Hartz  ;  the  Ven- 
dayah  Mts.,  Hindostan.  Found  sparingly  at  the  Chester 
and  Charlestown  syenite  quarries,  Mass.;  at  New  Haven, 
Thatchersville  and  Hadlyme,  Conn.,  and  other  points  in  the 
Connecticut  Valley  trap  ;  at  Phillipstown,  N.  Y.;  at  Bergen 
Hill,  N.  J. ;  in  trap,  in  the  copper  region  of  Lake  Superior ; 
in  beautiful  crystallizations  at  various  points  in  Nova 
Scotia. 

The  name  stilbite  is  derived  from  the  Greek  stilbe  lustre. 
It  has  also  been  called  desmine,  and  in  Germany  heulandite, 
where  heulandite  has  been  called  stilbite. 


Heulandite. 

Monoclinic.  In  right  rhomboidal  prisms  like  the  figure, 
with  perfect  pearly  cleavage  parallel  to  P  and  other 
planes  vitreous  in  lustre.  P  on  M  or  T=90°  ;  M  on  T 
r=129°  40'.  Color  white  ;  sometimes  reddish,  gray, 
brown.  Transparent  to  subtr°nsl  cent.  Folia  brit- 
tle. H.  =3-5-4.  G.  =2-17-  *•& 

Composition.  CaA10,6Si,  +  5  aq= Silica  59*1,  alu- 
mina 16-9,  lime  9'22,  water  14-8=100.  Contains 
1  to  2  per  cent,  of  Naf  or  K2  in  place  of  part  of  the 
Ca.  Blowpipe  characters  like  those  of  stilbite.  In- 
tumesces  and  fuses,  and  becomes  phosphorescent.  Dis- 
solves in  acid  without  gelatinizing. 

Diff.  The  very  pearly  lustre  of  the  cleavage  face  is  a 
marked  characteristic.  'Distinguished  from  gypsum  by  its 
hardness  ;  from  apophyllite  and  stilbite  by  its  crystals  ;  and 
from  the  latter  species  also  in  not  occurring  in  radiated 
crystallizations. 

Obs.  Found  in  amygdaloidal  cavities  and  fissures  in 
trap  ;  occasionally  in  gneiss,  and  in  some  metalliferoug 


304  DESCRIPTIONS   OP   MINERALS. 

veins ;  in  large  crystallizations  at  Berufiord,  Iceland ; 
and  Vendayah  Mts.,  Hindostan  ;  also  at  Isle  Skye  ;  near 
Glasgow ;  Fassa  Valley  ;  at  Bergen  Hill,  N.  J.,  in  trap  ;  at 
Hadlyme,  Conn.,  and  Chester,  Massachusetts,  on  gneiss  ; 
near  Baltimore,  on  a  syenitic  schist  (Beaumontite)  ;  at 
Peter's  Point  and  Cape  Blomidon,  and  other  places  in 
Nova  Scotia,  in  trap. 

The  species  was  named  by  Brooke  after  Mr.  Heuland, 
of  London. 

Brewstcrite.  Crystals  monoclinic  with  a  perfect  pearly  cleavage 
like  heulandite  ;  but  M  :  T  =  93°  40'.  H.=4i-5.  G.=2  45.  The  for- 
mula is  analogous  to  that  of  heulandite,  but  baryta  and  strontia  take 
the  place  of  the  lime  and  soda. 

Epistilbite.  Composition  like  that  of  beulandite,  but  occurs  in  short 
and  very  obtuse  rhombic  prisms,  (/A/=135°  10'),  at  Skye  ;  the  Faroe 
Ids.,  in  Iceland  ;  at  Margaretville,  in  Nova  Scotia. 

Mordenite.     Fibrous  mineral  from  Morden,  Nova  Scotia. 

Pilinitc.     In  slender  needles,  from  Silesia. 
'    Foresite.    Near  stilbite.     From  Elba. 


III.  MARGAROPHYLLITE  SECTION. 
Talc. 

Trimetric.  In  right  rhombic  or  hexagonal  prisms.  I/\l 
=  120°.  Usually  in  pearly  foliated  masses,  separating  easily 
into  thin  translucent  folia.  Sometimes  stellate,  or  diver- 
gent, consisting  of  radiating  laminae.  Often  massive,  con- 
sisting of  minute  pearly  scales  ;  also  crystalline  granular,  or 
of  a  fine  impalpable  texture. 

Lustre  eminently  pearly,  and  feel  unctuous.  Color  some 
shade  of  light  green  or  greenish  white ;  occasionally  silvery 
white;  also  grayish  green  and  dark  olive-green.  H.  =1- 
1*5;  easily  impressed  with  the  nail.  G.  =2*5-2-8.  Lam- 
inae flexible,  but  not  elastic. 

There  are  the  following  varieties : 

Foliated  Talc.  The  pure  foliated  talc,  of  a  white  or 
greenish-white  color. 

Soapstone  or  Steatite.  Gray  or  grayish  green,  and  either 
massive,  crystalline  granular,  or  impalpable  ;  very  greasy  to 
the  touch.  French  chalk  is  a  milk-white  variety,  with  a 
pearly  lustre.  Potstone  or  Lapis  Ollaris  is  impure  soap- 
stone  of  grayish-green  and  dark-green  colors,  and  slaty 
structure. 


HYDROUS   SILICATES — MARGAROPHYLLITE   SECTION.  305 

Indurated  Talc,  is  a  slaty  talc,  of  compact  texture,  and 
above  the  usual  hardness,  owing  to  impurities. 

Rensselaerite.  A  compact  crypto-crystalline  rock,  from 
St.  Lawrence  and  Jefferson  counties,  N.Y.,  of  white,  yellow, 
or  grayish-white  colors,  and  even  black.  It  has  sometimes 
the  form  and  cleavage  of  pyroxene,  and  is  in  part  at  least  a 
product  of  the  alteration  of  that  mineral. 

Composition.  ^H2  f  Mg  03  Si  =  Silica  62-8,  magnesia  33'5, 
water  3'7  =  100.  It  usually  contains  a  little  iron  replacing 
magnesium.  13. B.  infusible.  Moistened  with  cobalt  nitrate 
assumes  a  pink  tint.  Not  acted  upon  by  hydrochloric  acid. 
In  closed  tube  gives  a  little  water,  but  not  till  highly 
heated. 

Diff.  The  softness,  unctuous  feel,  foliated  structure,  when 
crystallized,  and  pearly  lustre  of  talc  are  good  characteris- 
tics. It  differs  from  mica  also  in  being  inelastic,  although 
flexible  ;  from  chlorite,  kaolinite,  and  serpentine  in  yielding 
little  water  when  heated  in  a  glass  tube.  Only  the  massive 
varieties  resemble  the  last-mentioned  species,  and  chlorite 
has  a  dark  olive-green  color.  Pyrophyllite,  which  cannot  be 
distinguished  in  some  of  its  varieties  from  talc,  becomes 
dark  blue  when  moistened  wifch  cobalt  nitrate  and  ignited. 

Obs.  Occurs  in  Cornwall,  near  Lizard  Point ;  at  rortsoy 
in  Scotland ;  at  Croky  Head,  Ireland ;  in  the  Greiner 
Mountain,  Saltzburg.  Handsome  foliated  talc  occurs  at 
Bridgewater,  Vt. ;  Smithfi  Id,  R.  I.  ;  Dexter,  Me.  ;  Lock- 
wood,  Newton  and  Sparta,  N.  J.,  and  Amity,  N.  Y.  On 
Staten  Island,  near  the  Quarantine,  both  the  common  and 
indurated  are  obtained  ;  at  Cooptown,  Md.,  green,  blue, 
and  rose-colored  talc  occur.  Steatite  or  soapstone  is  abun- 
dant, and  is  quarried  at  Grafton,  Vt.,  and  an  adjacent 
town  ;  at  Francestown  and  Orford,  N.  H.  It  also  occurs 
at  Keene  and  Richmond,  N.  H.  ;  at  Marlboro'  and  New 
Fane,  Vt.  ;  at  Middl  field,  Mass. ;  in  Loudon  County,  Va., 
and  at  many  other  places. 

Steatite  may  be  sawn  into  slabs  and  turned  in  a  lathe.  It 
is  used  for  firestones  in  furnaces  and  stoves,  and  fire-places. 
It  receives  a  polish  after  being  heated,  and  has  then  a  deep 
olive-green  color.  The  finer  kinds  are  made  into  images  in 
China,  and  into  inkstands  and  other  forms  in  other  coun- 
tries. Potstone  is  worked  into  vessels  for  culinary  pur- 
poses in  Lombardy.  The  harder  kinds  are  cut  into  gas  jets. 
Steatite  is  also  used  in  the  manufacture  of  porcelain  ;  it 


306  DESCRIPTIONS  OP  MINERALS. 

makes  the  biscuit  semi-transparent,  but  brittle  and  apt  to 
break  with  slight  changes  of  heat.  It  forms  a  polishing 
material  for  serpentine,  alabaster  and  glass.  "  French 
chalk"  is  used  for  removing  grease-spots  from  cloth,  as 
well  as  for  tracing  on  cloth.  When  ground  up,  soapstone 
is  employed  for  diminishing  the  friction  of  machinery. 

Pyrophyllite.— Agalmatolite,  in  part. 

Near  talc  in  crystallization,  cleavage,  its  occurrence  in 
fine-grained  massive  forms,  its  greasy  feel,  its  white  to  pale- 
green  colors,  varying  to  yellowish,  its  feeble  degree  of  hard- 
ness (1-2).  The  folia  are  sometimes  radiated.  G.=2'75- 
2-92. 

Composition.  An  aluminous  bisilicate,  instead  of  a  mag- 
nesian,  for  the  most  part  of  the  formula,  Al  09  Si3.  The 
Chesterfield,  S.  C.,;  mineral  afforded  Genth,  Silica  64-82, 
alumina  24*48,  iron  sesquioxide  0*96,  magnesia  0*33,  lime 
0-55,  water  5-25  — 100-39.  B.B.  whitens  and  fuses  with  dif- 
ficulty on  the  edges.  Gives  a  deep  blue  color  with  cobalt 
solution.  Yields  water  in  the  closed  tube.  Kadiated  varie- 
ties exfoliate  in  fan-like  forms. 

Obs.  Compact  pyrophyllite  is  the  chief  constituent  of  a 
kind  of  slate  or  schist,  which  is  used  for  slate  pencils,  and 
henee  is  called  pencil-stone.  Occurs  in  the  Urals  ;  at  \Ves- 
tana  in  Sweden;  in  Elfdalen,  with  cyanite  ;  foliated,  in 
North  Carolina,  in  Cottonstone  Mountain  ;  in  South  Caro- 
lina, in  Chesterfield  District,  with  lazulite  and  cyanite  ; 
Georgia,  in  Lincoln  County,  on  Graves  Mountain  ;  in  Ar- 
kansas, near  Little  Rock  ;  compact  slaty  in  the  Deep  River 
region,  N.  C.,  and  at  Carbonton,  Moore  County,  N.  C. 

Sepiolite. — Meerschaum  of  the  Germans. 

Usually  compact,  of  a  fine  earthy  texture,  with  a  smooth 
feel,  and  white  or  whitish  color  ;  also  fibrous,  white  to  bluish- 
green  in  color.  H.=2-2-5.  The  earthy  variety  floats  on 
water. 

Composition.  iH2  f  Mg  03  Si  4- 1£  aq  =  Silica  60-8,  magnesia 
27*1,  water  12-1  =  100.  B.B.  infusible,  or  fuses  with  great 
difficulty  on  the  thin  edges.  Much  water  in  a  closed  tube. 
A  pink  color  with  cobalt  solution. 

Occurs  in  Asia  Minor  in  masses  in  stratified  earthy  de- 
posits, and  is  extensively  used  for  pipe  bowls  ;  also  found  in 


HYDROUS   SILICATES — MARGAROPHYLLITE   SECTION.  307 

Greece,  Moravia,  Spain,  etc.  ;  also  in  fibrous  seams  at  a  sil- 
ver mine  in  Utah. 

Aphrodite.  Similar  to  the  preceding.  MgOsSi+fH.  From  Swe- 
den. Cimolite,  a  clay  from  the  Island  of  Argentiera,  Kimole  of  the 
Greeks.  Smectite,  a  kind  of  "Fuller's Earth,"  a  name  given  to  unc- 
tuous clays  used  in  fulling  cloth.  MontmoriUonite,  Stolpenite,  and 
Steargillite,  are  related  clay-like  minerals. 

Glauconite. — Green  Earth. 

In  dark  olive-green  to  yellowish-green  grains,  or  granular 
masses,  with  dull  lustre.  H.  =2.  G.^2^-2-4. 

Composition.  Essentially  a  silicate  of  iron  and  potassium. 
Formula  RR  012  Si4,  in  which  R  is  mainly  Fe  and  K,  with 
sometimes  Mg ;  and  R  is  Al,  but  sometimes  largely  Fe.  Analy- 
ses give  mostly  50-58  per  cent,  silica,  20-24  iron  protoxide, 
4-12  of  potash  and  8-12  of  water.  B.B.  fuses  easily  to  a 
magnetic  glass.  Yields  water  in  a  closed  tube. 

Obs.  In  a  more  or  less  pure  state  it  forms  thick  beds  in 
the  Cretaceous  formation,  and  also  in  the  Lower  Tertiary 
of  New  Jersey  ;  also  occurs  in  other  older  rock  formations 
down  to  the  Lower  Silurian.  Found  also,  first  by  Four- 
tales,  in  the  pores  of  corals  and  cavities  of  Rhizopod  shells 
over  the  existing  sea-bottom,  showing  it  to  be  a  marine 
product,  and  one  now  in  progress  of  formation.  The  grains 
of  the  Cretaceous,  Tertiary,  and  Lower  Silurian  beds  have 
been  shown  by  Ehrenberg  to  be  the  casts  of  the  interior  of 
shells  of  Rhizopods.  The  silica  has  been  supposed  to  come 
from  the  siliceous  secretions  of  a  minute  sponge  growing  in 
the  cavities  that  afterwards  became  occupied  by  the  glau- 
conite. 

Celadonite.  A  green  earth  with  53  per  cent,  of  silica,  from  amygda- 
loid, near  Verona.  Probably  an  impure  chlorite. 

Chloropal.  A  massive  greenish-yellow  to  pistachio-green  compact 
mineral,  somewhat  opal-like  in  appearance,  consisting  chiefly  of  silica, 
iron  sesquioxide,  and  water.  Montronite,  Pinguite,  Unghwarite  and 
Gramenite  are  varieties  of  it. 

Stilpnomelane.  Foliated  and  also  fibrous,  or  as  a  velvety  coating. 
Black  to  brownish  and  yellowish  bronze  in  color  and  lustre.  G.= 
3-8-4.  Chiefly  silica  and  iron  oxides,  with  8  to  9  per  cent,  of  water. 
Chalcodite  of  the  Sterling  Iron  Mine,  Antwerp,  Jefferson  County, 
N.  Y.,  is  here  included. 

Serpentine. 

Usually  massive  and  compact  in  texture,  of  a  dark  oil- 
green,  olive-green,  or  blackish-green  color  ;  also  pale  yel- 


308  DESCRIPTIONS   OP   MINERALS. 

lo wish-green,  brownish-yellow  and  brownish-red.  Occurs 
also  fibrous  and  lamellar.  The  lamellar  varieties  consist  of 
thin  folia,  sometimes  separable,  but  brittle  ;  colors  green- 
ish-white, and  light  to  dark  green.  Often  in  crystals  pseu- 
domorphous  after  chrysolite,  chondrodite,  and  some  other 
minerals. 

Lustre  weak  ;  resinous,  inclining  to  greasy.  Finer  varie- 
ties translucent;  also  opaque.  H.  =2'5-4.  G.  =  2'5-2*6. 
Feel  sometimes  a  little  unctuous.  Tough.  Fracture  con- 
choidal. 

Composition.  A  hydrous  silicate  of  magnesium,  like  talc, 
but  containing  much  more  water  and  much  less  silica. 
HjMg308Si2  +  l  aq  =  Silica  43 '48,  magnesia  43*48,  water 
13'04  =  100.  B.B.  fuses  with  much  difficulty  on  thin  edges. 
Yields  water  in  the  closed  tube.  Decomposed  by  hydro- 
chloric acid,  leaving  a  residue  of  silica.  In  some  kinds  the 
Mg  is  replaced  partly  by  Fe. 

Specimens  of  a  rich  oil-green  color,  and  translucent, 
bi caking  with  a  splintery  fracture,  are  sometimes  called 
precious  serpentine,  and  the  opaque  kind,  common  serpen- 
tine. 

Fibrous  serpentine  with  a  silky  lustre  is  called  Chrysotile, 
and  also  Amianthus.  Unlike  asbestus,  which  it  resembles, 
it  affords  much  water  in  a  closed  tube.  Metaxite,  Picro- 
lite,  and  Baltimorite  are  coarse  fibrous  kinds.  A  foliated 
variety,  from  Hoboken,  N.  J.,  was  named  Marmolite,  be- 
fore it  was  known  to  be  serpentine.  Antiyorite  is  a  foli- 
ated variety.  Williamsite  is  similar.  Refdanskite  contains 
nickel. 

A  porcelain-like  serpentine — the  Meerschaum  of  Taberg 
and  Sala — has  been  called  Porcello$)hite  ;  and  a  resin-like 
variety,  Retinalite  and  Vorhauserite. 

Diff.  The  distinguishing  characters  are  feeble  lustre, 
somewhat  resinous,  compact  structure,  little  hardness,  being 
so  soft  as  to  be  easily  cut  with  a  knife,  and  specific  gravity 
not  over  2*6. 

Obs.  Serpentine  occurs  as  a  rock,  and  the  several  varie- 
ties mentioned  either  constitute  the  rock  or  occur  in  it. 
Occasionally  it  is  disseminated  through  granular  limestone, 
giving  the  latter  a  clouded  green  color  :  this  is  the  verd  an- 
tique marble,  called  also  Opliiolyte. 

Serpentine  occurs  in  Cornwall  ;  near  Portsoy  in  Aber- 
deenshire,  in  Corsica,  Siberia,  Saxony,  Norway  at  Snarum. 


HYDROUS   SILICATES — MARGAROPHTLLITE   SECTION.  309 

In  the  United  States  it  occurs  at  Phillipstown,  Port  Henry, 
Gouverneur,  Warwick,  N.  Y.  ;  Newburyport,  Westfield, 
and  Bltindford,  Mass.;  at  Kellyvale  and  New  Fane,  Vt. ; 
Deer  Isle,  Maine  ;  New  Haven,  Conn. ;  Bare  Hills,  Md. ; 
Hoboken,  N.  J. ;  at  Brewster's,  Putnam  County,  N.  Y., 
where  it  occurs  pseudomorphous  after  chondrodite,  chlo- 
rite, enstatite,  biotite,  etc.  ;  in  Canada  at  Orford,  Ham,  Bol- 
ton,  etc. 

Serpentine  forms  a  handsome  marble  when  polished,  es- 
pecially when  mixed  with  limestone,  constituting  verd- 
antique  marble.  Its  colors  are  often  beautifully  clouded, 
and  it  is  much  sought  for  as  a  material  for  tables,  jambs 
for  fire-places,  and  ornamental  in-door  work.  Exposed  to 
the  weather,  it  wears  uneven,  and  soon  loses  its  polish. 
Chromic  iron  is  usually  disseminated  through  it,  and  in 
creases  the  variety  of  its  colors.  Near  Milford  and  New 
Haven,  Conn.,  a  handsome  verd-antique  marble  occurs 
which  was  formerly  worked.  A  white  limestone,  dotted 
and  spotted  with  green  serpentine  at  Port  Henry,  Essex 
County,  N.  Y.,  is  much  esteemed  for  its  beauty,  and  is  now 
extensively  worked.  The  name  serpentine  alludes  to  the 
varied  green  colors  of  such  rocks. 

Bowenite  from  Smithfield,  R.  I.,  has  the  composition  of  serpentine, 
but  the  hardness  5  '5-6,  and  the  aspect  of  nephrite,  with  G.  —2  '59-2'  8. 

Bastlte  or  Schiller  Spar,  is  a  foliated  pyroxene  or  bronzite  altered 
nearly  to  serpentine.  AntUlite  is  similar. 

Deweylite. 

Massive.  Whitish,  yellowish,  brownish-yellow,  greenish, 
reddish,  in  color,  with  the  aspect  of  gum  arabic  or  a  resin. 
Very  brittle.  H.  =2-3  5.  G.  =  l'9-2-25. 

In  composition  near  serpentine  but  containing  20  per 
cent,  of  water.  From  Middlefield,  Mass.  ;  Bare  Hills, 
Maryland  (Qymnito);  T^xas,  Pa.,  and  from  the  Fleims  Val- 
ley, Tyrol. 

Cerolite.  Related  to  deweylite  ;  from  Silesia.  Limbachito  from  Lim* 
bach,  and  Zoblitzite  from  Zoblitz,  are  similar. 

Hydrophite.  Like  deweylite,  but  containing  iron  in  place  of  part 
of  the  magnesium.  From  Taberg  in  Smaoland.  Jenkinsite  is  a 
fibrous  variety,  occurring  on  magnetite,  at  O'Neil's  mine  in  Orange 
County,  N.  Y. 

Genthite  or  Nickel-gymnite.  Similar  to  deweylite,  but  containing 
much  nickel  and  G.=  2 '4,  analysis  affording  Silica  35 '36,  nickel  pro- 
toxide 30-64,  iron  protoxide  0'24,  magnesia  14*60,  lime  0'26,  water 


310  DESCRIPTIONS   OP   MINERALS. 

19- 09 =100 -19.  From  Texas,  Pa.  ;  Webster,  N.  C.  ;  Michipicoton 
Island,  Lake  Superior ;  Malaga,  Spain  ;  Saasthal,  Upper  valois. 
Eottisite  is  similar. 

Saponite. 

Soft,  clay-like,  of  the  consistence  before  drying  of  cheese 
or  butter,  but  brittle  when  dry.  Color  white,  yellowish, 
grayish-green,  bluish,  reddish.  Does  not  adhere  to  the 
tongue. 

Composition.  A  hydrous  silicate  of  magnesia  containing 
some  alumina. 

From  Lizard's  Point,  Cornwall,  in  serpentine.  Also  from 
geodes  of  datolite,  Roaring  Brook,  Conn.  ;  in  trap,  north 
shore  of  Lake  Superior. 

Eaolinite. 

Trimetric.  /A  7=  120°.  Occurs  massive,  clay-like,  but 
consisting  usually  of  thin,  microscopic,  rhombic  or  hex- 
agonal, crystals  ;  either  compact,  friable,  or  mealy. 

Color  wliite,  grayish-white,  yellowish,  sometimes  brown- 
ish, bluish,  or  reddish.  Scales  transparent  or  translucent  ; 
flexible,  inelastic,  greasy  to  the  touch.  H.  =  1-2 '5.  G.= 
2-4-2-6. 

Composition.  H2A1  08  Si2  +  l  aq= Silica  46 '4,  alumina  39*7, 
water  13'9  =  100.  The  similarity  of  the  composition  to  that 
of  serpentine  will  be  seen  on  comparing  the  two  formulas. 
B.  B.  infusible.  A  blue  color  with  cobalt  solution.  Yields 
water  in  the  closed  tube.  Insoluble  in  acids. 

Obs.  The  soapy  feel  of  kaolinite  distinguishes  a  clay  con- 
sisting of  it  from  other  kinds  of  clay  ;  and  when  common 
clays  are  "  unctuous  "  it  is  usually  owing  to  the  presence  of 
kaolinite.  Kaolinite  has  been  made  through  the  decompo- 
sition of  aluminous  minerals,  and  especially  the  potash  and 
soda  feldspars,  orthoclase,  albite,  and  oligoclase.  In  the 
case  of  these  feldspars  the  process  (1)  removes  the  alkalies  ; 
(2)  leaves  the  alumina,  or  a  large  part  of  it,  and  part  of  the 
silica  ;  and  (3)  adds  water.  So  that,  with  orthoclase,  K2Al 
O16  Si6  becomes  changed  to  H2A1 08Si2  +  l  aq  ;  half  the  water 
which  is  added  replaces  K2  which  is  removed.  Many  gran- 
ites, gneisses,  and  other  feldspar-bearing  rocks  undergo 
rapidly  this  change,  so  that  extensive  beds  of  kaolinite  have 
been  formed  and  are  now  making  in  many  regions.  The 
kaolinite  is  usually  washed  out  by  streams  or  the  waves  from 
the  decomposed  material  to  make  the  large  pure  deposits. 


HYDROUS   SILICATES — MARGAROPHYLLITE   SECTION.  311 

The  New  Jersey  clay-beds  of  the  Cretaceous  formation  are 
mainly  kaolinite,  and  have  been  thus  formed.  In  other 
cases  permeating  waters  have  washed  out  the  oxides  of  iron 
present,  and  have  left  the  white  clay  in  place.  A  pure 
kaolinite  bed  occurs  at  Brandon,  Vermont,  along  with  a 
limonite  bed,  where  the  rock  decomposed  was  probably  a 
feldspathic  hydromica  slate.  Most  of  the  limonite  beds  of 
Western  New  England  afford  kaolinite  ;  yet  it  is  generally 
more  or  less  colored  by  iron  oxide. 

Common  clays  consist  of  finely-powdered  feldspar,  quartz, 
and  other  mineral  material,  with  often  more  or  less  kaoli- 
nite. They  burn  red  in  case  they  contain  iron  in  the  state 
ordinarily  present  in  them  of  iron  carbonate,  or  hydrous 
iron  oxide  (limonite),  or  in  combination  with  an  organic 
acid,  or  in  some  other  alterable  state  of  composition,  heat 
driving  off  the  carbonic  acid  or  water,  or  destroying  the  or- 
ganic acid,  and  so  leaving  the  red  oxide  of  iron  (or  sesqui- 
oxide),  or  favoring  its  production.  But  the  iron  may  be  so 
combined  as  not  to  give  the  red  color;  and  this  has  been 
found  to  be  true  with  the  clays  from  which  the  cream-col- 
ored Milwaukee  (Wisconsin)  brick  are  made,  and  that  of 
other  clay  beds  in  that  vicinity.  The  iron  may  be  there  in 
the  state  of  the  silicate,  zoisite,  or  epidote. 

Pure  kaolinite  (or  kaolin  as  it  is  ordinarily  called)  is 
used  in  making  the  finest  porcelain.  For  this  purpose  it  is 
mixed  with  pulverized  feldspar  and  quartz,  in  the  proportion 
needed  to  give,  on  baking,  that  slight  incipient  degree  of 
fusion  which  renders  porcelain  translucent.  The  name 
kaolin  is  a  corruption  of  the  Chinese  word  Kauling,  mean- 
ing high  ridge,  the  name  of  a  hill  near  Jauehau-Fu,  where 
the  mineral  is  obtained;  and  i\\Qpetuntze  (peh-tun-tsz)  of  the 
Chinese,  with  which  the  kaolin  is  mixed  in  China  for  the 
manufacture  of  porcelain,  is,  according  to  S.  W.  Williams, 
a  quartzose  feldspathic  rock*  consisting  largely  of  quartz. 
The  word  porcelain  was  first  given  to  China-ware  by  the 
Portuguese,  from  its  resemblance  to  certain  sea-shells  called 
Porcellana;  they  supposed  it  to  be  made  from  shells,  fish- 
glue,  and  fish-scales  (8.  W.  Williams). 

The  impure  kaolin  is  used  for  stoneware  and  fire-bricks. 
The  presence  of  iron,  in  any  state,  makes  a  clay  more  or 
less  fusible,  and  therefore  an  unfit  material  for  fire-bricks. 
But  a  little  of  it  exists  in  all  clays  employed  for  making  or- 
dinary bricks,  and  hence  their  red  color. 


312  DESCRIPTIONS  OF  MINERALS. 

Pholerite,  Hattoysite,  Smectite,  Severite,  Glagerite,  Lenzinite,  Bole,  Li 
thomarge,  are  names  of  clay-like  minerals. 

Finite. 

Amorphous,  and  usually  cryptocrystalline ;  but  often 
having  the  form  of  the  crystals  of  other  minerals  from  the 
alteration  of  which  it  has  been  made.  Colors  grayish,  green- 
ish, brownish,  and  sometimes  reddish.  Lustre  feeble;  waxy. 
Translucent  to  opaque.  Acts  like  a  gum  on  polarized  light, 
and  thus  indicates  the  absence  of  true  crystallization,  even 
when  under  the  forms  of  crystals.  H.=2'5-3.  G.—  2-6-2'85. 

Composition.  Mostly  (H3K)2A12  Qm  Sis.  The  pinite  of  Saxony 
afforded  Silica  46-83,  alumina  27*65,  iron  sesquioxide  8 -71, 
magnesia  1-02,  lime  0*49,  soda  0'40,  potash  6 '52,  water  3 '83 
=  99-42  ;  and,  in  another  analysis,  potash  10*74.  The  phy- 
sical characters  ally  it  to  serpentine,  and  also  nearly  the 
atomic  ratio,  and  it  may  be  viewed  as  a  potash-alumina  ser- 
pentine. But  at  the  same  time  it  has  very  nearly  the  com- 
position of  a  hydrous  potash  mica,  or  damourite  (see  next 
page). 

Obs.  The  varieties  are  pseudomorphs  after  different  min- 
erals, and  hence  comes  a  part  of  their  variations  in  compo- 
sition. They  include  Pinite,  from  the  Pini  Mine,  near 
Schneeberg  and  elsewhere  ;  Gieseckite,  pseudomorph  after 
nephelite  from  Greenland,  and  from  Diana,  N.  Y. ;  Dysyn- 
tribite,  from  Diana,  identical  with  gieseckite  ;  Pinitoid, 
from  Saxony  ;  Wilsonite,  from  Bathurst,  Canada,  having 
the  cleavage  of  scapolite  ;  Terenite,  from  Antwerp,  N.  Y., 
like  Wilsonite  ;  Agalmatolite,  or  Pagodite,  from  China,  be- 
ing one  of  the  materials  for  carving  into  images,  ornaments, 
models  of  pagodas,  etc. ;  gigantolite  and  iberite,  which  have 
the  form  of  iolite. 

Polyargite,  Eosite,  Cataspilite,  Biharite  are  related  materials. 

Palagonite.  Yellow  to  brownish  yellow,  garnet-red  to  black  in 
color,  and  resinous  to  vitreous  in  lustre.  The  material  of  some  tufas, 
and  the  result  of  change  through  the  agency  of  steam  or  hot  water  at 
the  time,  probably,  of  the  deposition  of  the  material.  From  tufas  of 
Iceland,  Germany,  Italy,  Sicily,  and  named  from  Palagonia,  in  Sicily. 

HYDROMIOA  GROUP. 

The  following  species  are  mica-like  in  cleavage  and  aspect, 
but  talc-like  in  wanting  elasticity,  greasy  feel,  ajid  pearly 
lustre.  They  arc  sometimes  brittle.  Common  mica,  mus- 


HYDROMICA   GROUP.  313 

covite,  readily  becomes  hydrated  on  exposure  ;  but  hydrous 
micas  are  not  all  a  result  of  alteration.  The  Hydromica 
slates  form  extensive  rock-formations,  equal  to  those  of  the 
ordinary  mica  schists.  They  were  for  the  most  part  called 
Talcose  slates  (or  Talk-scUiefer  in  German)  from  their  greasy 
feel,  until  the  fact  was  ascertained  that  they  contained  no 
magnesia  :  a  point  demonstrated  for  the  Taconic  slates  of 
the  western  border  of  Massachusetts,  by  C.  Dewey,  in  1819, 
and  later,  by  G.  F.  Barker,  for  those  of  Vermont.  Finite 
is  related  in  composition,  but  is  not  micaceous. 

Margarodite. 

Like  muscovite  (page  267),  but  inelastic. 

Composition.  Specimens  from  the  topaz  vein,  Trunftmll, 
Conn.,  afforded  Silica  46'50,  alumina  33 '91,  iron  sesquiox- 
ide  2-69,  magnesia  0-90,  soda  JJ  '70,  potash  7'32,  water  4-63, 
fluorine  0-82,  chlorine  0-31  =  99-78.  Another  from  Litch- 
field,  Conn.,  accompanying  cyanite,  afforded  water  5*26  per 
cent.,  soda  4-10,  potash  6-20,  showing  a  large  percentage  of 
soda.  It  is  probable  that  both  of  these  micas  were  originally 
hydrous. 

Damourite. 

Mica-like,  consisting  of  an  aggregation  of  fine  pearly  scales, 
yellow  to  white  in  color. 

Composition.  Near  margarodite,  being  a  hydrous  potash 
mica.  A  specimen  from  Brittany  afforded  Silica  45-22, 
alumina  37 '85,  potash  11  '20,  water  5-25  =  99-52.  The  quan- 
tivalent  ratio  for  the  protoxide,  sesquioxide,  silica,  and 
water  is  1:  9: 12:2,  instead  of  that  of  margarodite,  which  is 
1:6:9:2.  A  schistose  hydromica  slate  from  Lehigh  County, 
Pennsylvania,  afforded  Dr.  Genth,  Silica  49 '92,  alumina 
34-06,  iron  sesquioxide  0*91,  magnesia  1/77,  lime  0-11,  soda 
0-74,  potash  6 -94,  water  6  -52  =  100-97. 

Obs.  From  a  locality  of  cyanite  in  Brittany,  and  another 
in  Warmland  ;  also  the  constituents  of  a  garnetiferous  schist 
at  Salm-Chateau,  in  Belgium;  and  in  part  of  extensive 
schistose  formations  in  Vermont,  Western  Massachusetts, 
"Western  Connecticut,  and  also  just  west  of  New  Haven, 
Connecticut ;  Eastern  Pennsylvania,  etc. 


314  DESCRIPTIONS  OF   MINERALS. 

For  other  analyses  of  hydromica  slates,  see  Dr.  Genth's  report  on 
the  Mineralogy  of  Pennsylvania ;  also  Geological  Report  of  F.  Prime, 
Jr.,  for  1874,  p.  12. 

Parophitc.  The  material  of  a  schist  or  slate — Parophite  Schist — 
which  cuts  like  massive  talc,  is  of  greenish,  yellowish,  reddish,  and 
grayish  colors,  and  is  probably  a  damourite  or  hydromica  slate,  with 
some  free  silica  (quartz).  An  analysis  afforded  Silica  48 '46,  alumina 
27*55,  iron  protoxide  5 '08,  magnesia  2 '02,  lime  2 '05,  ^oua  2 '35,  potash 
516,  water  7 14=99 '81.  It  is  from  Pownal,  Vt.,  and  St.  Nicholas, 
Stanstead,  and  other  neighboring  parts  of  Canada. 

Sericite.  A  damourite-like  mineral,  with  the  pearly  lustre  of  talc, 
and  the  composition  of  a  hydrous  mica  ;  it  is  the  basis  of  a  glossy 
schist  ;  near  Wiesbaden.  The  scales  are  described  by  Rosenbusch  as 
appearing  fibrous  when  highly  magnified.  Analysis  afforded  Silica 
49-00,  alumina  23'65,  iron  protoxide  8*07,  magnesia  0  94,  lime  0*63, 
soda  1*75,  potash  9 '11,  water  3 '47,  titanic  dioxide  1/39,  silicon  fluoride 
1-60=100-14. 

Paragonite.  A  hydrous  mica  containing  soda  in  place  of  potash. 
From  Mount  Campione,  in  the  region  of  St.  Gothard.  Color  whitish, 
grayish,  yellowish,  greenish.  Analysis  afforded  Silica  46 '81,  alu- 
mina 40  06,  magnesia  0'65,  lime  1*26,  soda  6 '40,  potash  trace,  water 
4-82=100.  Pregrattite.  from  the  Tyrol,  afforded  soda  7'06,  potash 
1-71,  water  5 '04  ;  it  exfoliates  like  the  Vermiculites.  Cossaite  is  here 
included. 

Groppite.  A  rose-red  to  brownish-red  foliated  mineral  from  Gropp- 
torp,  Sweden. 

EuphyUite.  Mica -like,  with  folia  rather  brittle,  pearly  lustre, 
white  or  colorless.  Contains  much  sodium.  An  analysis  afforded 
Silica  41-6,  alumina  42*3,  lime  1 -5,  potash  3 '2,  soda  5 '9,  water  5 '5 =100. 
Occurs  with  corundum  at  Unionville,  Delaware  County,  Pa. 

(EUacherite.  Mica-like  ;  strong  pearly  in  lustre,  grayish  white  to 
white  ;  elastic.  Analysis  obtained  7 '61  potash,  1'42  soda,  4*65  baryta, 
and  4'43  water,  besides  silica,  alumina,  etc. 

Cookeite.  In  minute  mica-like  scales,  and  in  slender  six-sided 
prisms.  Affords  only  2 '57  of  potash,  with  2 '82  of  lithia  ;  the  water 
13*41  per  cent.  Occurs  on  crystals  of  red  tourmaline  at  Hebron  and 
Paris,  Me.,  and  has  proceeded  from  its  alteration.  Named  after  Prof. 
J.  P.  Cooke,  of  Cambridge,  Mass. 

Voigtite  is  the  mica  of  a  granite  at  Ehrenberg,  near  Ilmenau,  which 
has  the  composition  of  biotite,  plus  9  to  10  per  cent,  of  water. 

Roscoelite.  A  vanadium-mica,  of  dark  brownish-green  color,  occur- 
ring in  micaceous  scales,  and  affording  over  20  per  cent,  of  vanadium 
oxides,  along  with  47*69  of  silica,  14'10  of  alumina,  7 '59  of  potash, 
4*96  of  water,  and  a  little  magnesia  and  soda.  From  Granite  Creek 
Gold  Mine,  El  Dorado  County,  California. 

Fahlunite0 

In  six  and  twelve-sided  prisms,  usually  foliated,  parallel 
to  the  base,  but  owing  its  prismatic  forms  to  the  mineral 
from  which  it  was  derived.  Folia  soft  and  brittle,  of  a 


HYDROUS    SILICATES.  315 

grayish-green  to  dark  olive-green  color,  and  pearly  lustre. 
G.  =2-7. 

Composition.  A  hydrous  silicate  of  aluminum  and  iron 
with  little  or  no  alkali,  and  in  this  last  point  differing  from 
pinite.  An  average  specimen  afforded  Silica  44-60,  alumina 
30-10,  iron  protoxide  3-86,  manganese  protoxide  2-24,  mag- 
nesia 6*75,  lime  T35,  potash  1-98,  water  9'35  =  100-2-3. 
B.B.  fuses  to  a  white  glass.  In  a  closed  tube  gives  water. 
Insoluble  in  acids. 

Diff.  It  is  distinguished  from  talc  by  affording  much 
water  before  the  blowpipe,  and  readily  by  its  association 
with  iolite,  and  its  large  hexagonal  forms,  with  brittle  folia. 

Obs.  Fahlunite  has  been  derived  from  the  alteration  of 
iolite.  The  quantivalent  ratio  of  iolite  for  the  protoxides, 
sesquioxides,  and  silicon  is  1:3:5;  and  for  fahlunite,  the 
same,  with  1  for  the  water,  making  the  whole  1:3:5:1.  The 
hydration  appears  to  go  on  at  the  ordinary  temperature, 
and  in  some  localities  all  the  iolite  to  a  considerable  depth 
in  the  rock  is  changed  to  fahlunite.  There  are  different 
varieties,  depending  on  the  amount  of  water,  and  the  con- 
ditions under  which  the  change  has  taken  place.  The 
names  they  have  received  are  Hijdrous  Iolite,  Chlorophyllite, 
Esrnarkite,  Aspasiolite,  Pyrargillite,  Triclasite.  Fahlunite 
was  so  named  from  its  locality,  Fahlun,  Sweden  ;  and  Chlo- 
Tophyllite  from  its  greenish  color  and  foliated  structure  ;  the 
specimens  to  which  it  was  given  occurring  at  Unity,  N.  H. 
Haddam,  Ct.,  is  another  locality.  Gigantolite,  Iberite,  are 
also  altered  iolite,  but  they  contain  potash,  and  belong 
hence  to  the  Pinite  Group. 

Hisingerite. 

Massive  ;  reniform  ;  of  a  black  to  brownish-black  color, 
yellowish-brown  streak,  greasy  lustre  inclining  to  vitreous. 
H.=3.  G.=3'045. 

Composition.  A  hydrous  iron  silicate.  Silica  35'9,  iron 
sesquioxide  42'6,  water  21-5  =  100.  But  in  some  analyses 
part  of  the  iron  is  in  the  protoxide  state.  B.B.  fuses  with 
difficulty  to  a  magnetic  slag. 

Obs.  From  Sweden,  Norway,  Finland.  Scotiolite  and 
Deyeroite  are  referred  to  it.  Melanolite,  from  Milk-Row 
quarry,  near  Charlestown,  Mass.,  is  related  in  composition, 
if  the  material  analyzed  was  a  pure  species. 


316  DESCRIPTIONS   OF   MINERALS. 

Approaches  in  composition  the  chlorites,  and  may  belong 
to  that  group. 

Gillingite  from  Sweden,  including  Thraulitc  from  Bavaria,  EpicMo- 
rite,  and  Lillite,  are  other  hydrous  silicates  containing  iron . 

Ekmannite,  foliated,  chlorite-like,  occurs  in  the  rifts  of  magnetite, 
in  Sweden  ;  it  is  a  hydrous  iron  silicate,  but  the  iron  is  mostly  in  the 
protoxide  state. 

Neotocite  (Stratopeite)  and  Wittingite  are  results  of  the  alteration  of 
rhodonite,  and  contain  manganese.  Stubelite  also  contains  manganese 
oxide. 

Slrigomte  from  Striegau,  Siberia,  and  Jollyte  from  Bodenmais  in 
Bavaria,  are  hydrous  silicates  of  aluminum  and  iron,  with  little  mag- 
nesium. 

CHLORITE  GROUP. 

The  chlorite  group  includes  the  hydrous  Subsilicates  of 
the  Margarophyllite  Section  and  also  some  related  species 
that  are  Unisilicates.  The  proportion  of  silica  is  small,  the 
percentage  afforded  by  analyses  being  under  38,  and  mostly 
under  30.  The  minerals  when  well  crystallized  are  foliated 
like  the  micas,  and  have  the  plane  angle  of  the  base  of  the 
crystals  120°,  but  the  folia  are  inelastic  and  in  some  species 
brittle.  They  also  occur  in  fibrous  and  in  fine  granular  and 
compact  forms,  and  the  latter  are  usually  most  common. 
Green,  varying  from  light  to  blackish  green,  is  the  prevail- 
ing color,  yet  gray,  yellowish,  reddish,  and  even  white  and 
black  also  occur ;  and  the  colored  transparent  or  translu- 
cent are  dichroic.  The  green  color  is  owing  to  the  presence 
of  iron,  and  fails  only  in  species  containing  little  or  none 
of  it.  All  of  the  species  yield  water  in  a  closed  tube. 
The  quantivalent  (or  combining-power)  ratio  for  R  +  &  and 
Si  is,  in  the 

Pyrosclerite  subdivision 1:1. 

Chlorite  subdivision 1  :  i,  1 :  f,  1 :  £. 

Chloritoid  subdivision 1 :  £  to  1 :  £. 

The  chlorite  subdivision  includes  Penninite,  Ripidolite 
and  Prochlorite,  together  with  some  related  dark -green  to 
blackish-green  species.  Some  species  of  this  subdivision 
characterize  extensive  rock  formations,  making  chlorite 


CHLORITE   GROUP.  317 

schist  or  slate  ;  and  they  give  rise  also  to  chloritic  varieties 
of  other  rocks.  Moreover,  chlorite  is  a  result  of  the  altera- 
tion of  pyroxene,  hornblende,  and  some  other  iron-bearing 
minerals ;  and  pyroxcnic  igneous  rocks,  like  doleryte,  are 
often  strongly  chloritic  (as  revealed  by  the  microscopic 
examination  of  thin  transparent  slices),  in  consequence  of 
this  alteration — but  alteration  that  took  place  before  the 
rock  had  cooled.  Such  green  chloritic  material,  where  the 
species  is  not  determinable,  has  been  called  Viridite.  The 
cavities  in  amygdaloid  are  often  lined,  and  sometimes  filled, 
by  a  species  of  chlorite,  which  was  made  from  certain  con- 
stituents of  the  amygdaloid  in  the  manner  just  stated  ;  and 
the  rocks  adjoining  trap  dikes  are  at  times  penetrated  by 
chlorite  made  in  them  by  means  of  the  heat,  and  the  mois- 
ture contained  in  them  or  ascending  with  the  erupted  rock. 

Pyrosclerite. 

Trimetric  or  monoclinic.  Mica-like  in  cleavage ;  folia 
flexible,  not  elastic,  and  pearly  in  lustre.  Color  apple-green 
to  emerald-green.  H.=3.  G.  =2'74. 

Composition,  (f  Mgs  JA1),  018  Si3  +  3  aq  =  Silica  38 '9,  alu- 
mina 14-8,  magnesia  34-6,  water  11'7=100.  B.B.  fuses  to  a 
grayish  glass  ;  gelatinizes  with  hydrochloric  acid. 

Obs.  Occurs  in  serpentine,  on  Elba. 

Chonicrite  (Metaxoite)  is  related  to  the  above  in  composition,  but 
affords  13  to  18  per  cent,  of  linie. 

Vermiculite. 

Mica-like  in  cleavage.  Grayish,  brownish,  and  yellowish- 
brown  in  color.  In  aggregated  scales.  Also  in  large  mi- 
caceous crystals  or  plates.  Laminae  flexible,  not  elastic. 
Lustre  pearly. 

Composition.  Mg3  (Fe,Al)  012Si3.  When  heated  it  exfo- 
liates, and  when  scaly-granular  the  scales  open  out  into 
worm-like  forms  ;  and  thence  the  name,  from  the  Latin 
vermicular,  I  breed  worms ;  B.B.  fuses  finally  to  a  gray 
mass.  From  Milbury,  Mass. 

Jefferisite  is  a  similar  mineral  in  composition  and  exfoliation,  occur- 
ring in  broad  folia.  Composition  £Mg3£(Fe2,Al2)O12  Si3.  From  veins 
in  serpentine  in  Westchester,  Pa.  Culsageeite  from  Culsagee,  North 


318  DESCRIPTIONS   OP  MINERALS. 

Carolina  ;  Hallite  from  Lerni,  Delaware  Co.,  Pa. ;  Protovermiculite 
from  Magnet  Cove,  Ark.,  are  other  micaceous  hydrous  unisilicates 
similar  to  vermiculite  and  jefferisite  in  exfoliation.  Kerrite  and 
Maconite  are  related  to  the  above.  They  are  from  Franklin,  Macon 
Co.,  North  Carolina.  Pdhamite  is  from  Pelham,  Mass. 

Penninite. — Chlorite  in  part.     Pennine. 

Khombohedral.  Cleavage  basal  and  highly  perfect,  mica- 
like.  Also  massive,  consisting  of  an  aggregation  of  scales, 
and  cryptocrystalline. 

Color  green  of  various  shades  ;  also  yellowish  to  silver- 
white,  and  rose-red  to  violet.  Lustre  pearly  on  cleavage 
surface.  Transparent  to  translucent.  Laminae  flexible, 
not  elastic.  H.  =  2-2-5,  3  on  edges.  G.= 2 -6-2-85. 

Composition.  A  specimen  from  Zermatt,  in  the  Pennine 
Alps,  aiforded  Silica  33-64,  alumina  10'64,  iron  sesquioxide 
8-83,  magnesia  34-95,  water  12-40=100-46.  The  rose-red, 
from  Texas,  Pa.,  gave  Silica  33*20,  alumina  11-11,  chro- 
mium oxide  6-85,  iron  sesquioxide  1*43,  magnesia  35 '54, 
water  12-95,  lithia  and  soda  0-28,  potash  0-10  =  101-46. 
Other  Texas  specimens  afforded  0-90  to  4'78  per  cent,  of 
chromium  oxide.  B.B.  exfoliates  somewhat  and  fuses  with 
difficulty.  Partially  decomposed  by  hydrochloric  acid,  and 
wholly  so  by  sulphuric  acid. 

From  Zermatt,  Ala  in  Piedmont,  the  Tyrol,  etc.  Kdm- 
mererite,  Rhodochrome,  and  Rhodophyllite  include  the  red- 
dish variety  from  near  Miask,  Russia ;  Texas,  Pennsylva- 
nia ;  etc.  Pseudomorphs  after  hornblende,  named  Loganitt 
have  the  composition  of  this  species  ;  and  so  has  the  mas- 
sive mineral  called  P seudopliite  and  Allophite. 

Ddessite.  A  fibrous  mineral  near  the  above  in  composition,  from 
amygdaloid  at  Oberstein. 

Euralite  is  an  amorphous  chlorite  near  Penninite,  from  Eura,  Fin- 
land ;  from  amygdaloid. 

Diabaniite  (Diahantoclironyri]  is  a  chlorite  from  amygdaloid.  A 
Farmington  (Conn.)  specimen  afforded  Hawes,  Silica  33 "68,  alumina 
10'84,  iron  sesquioxide  2'86,  iron  protoxide  24'33,  MnO  and  CaO  I'll, 
magnesia  16'52,  soda  0'33,  water  10'02=99-69. 

Chlorophwite  is  a  doubtful  species  of  chlorite,  from  amygdaloid. 

Ripidolite.— Chlorite,  in  part. 

Monoclinic.  Similar  in  cleavage  and  mica-like  character 
to  penninite,  and  also  in  its  colors,  lustre,  hardness  and 
specific  gravity. 


CHLORITE   GROUP.  319 

Composition.  A  specimen  from  Chester  Co. ,  Pennsylvania, 
afforded  Silica  31*34,  alumina  17-47,  chromium  sesquioxide 
1 -69,  iron  sesquioxide  3*85,  magnesia  33-44,  water  12-60= 
100  "39.  B.B.  and  with  acids  nearly  like  penninite.  A  va- 
riety from  Willimantic,  Ct.,  exfoliates  like  vermiculite  and 
jefferisite. 

Kotscliubeite  is  a  red  variety  from  the  Urals. 

Clinochlore  and  Grastite  are  here  included.  Occurs  at 
Achmatovsk  and  elsewhere  in  the  Urals  ;  at  Ala,  Piedmont ; 
at  Zermatt ;  at  Westchester,  Union ville  and  Texas,  Pa. ;  at 
Brewster's,  N.  Y. 

Prochlorite. — Chlorite  in  part. 

Hexagonal.    Similar  in  cleavage  and  mica-like  characters 
the  preceding.     Color  green   to  blackish-green  ;   some- 
imes  red  across  the  axis  by  transmitted  light.     Laminae 
>t  elastic. 

Composition.  A  specimen  from  St.  Gothard  afforded  Sili- 
25*36,  alumina  18*56,  iron  protoxide  28 '79,  magnesia 
17*09,  water  8-96  =  98-70  ;  and  a  North  Carolina  specimen, 
Silica  24-90,  alumina  21*77,  iron  sesquioxide  4*60,  iron 
protoxide  24*21,  manganese  protoxide  1*15,  magnesia  12*78, 
water  10-59=100.  B.B.  same  as  for  preceding. 

Lophoite,  Ogcoite,  Helminthe  belong  here.  Occur  at  St. 
Gothard,  at  Greiner  in  the  Tyrol,  at  Traversella  in  Pied- 
mont, and  many  other  places  in  Europe.  Also  at  Steele's 
Mine,  N.  C. 

Leuchtenbergite  is  a  proclilorite  with  the  base  almost  solely  magne- 
sium. 

Aphrosiderite,  Metachlorite  are  near  the  above  in  composition. 

Venerite  is  a  pale-green  earthy  chlorite,  from  a  magnetite  mine  in 
Berks  County,  Pa. 

Corundophilite  is  a  chlorite  near  prochlorite  in  composition.  Occurs 
with  corundum  at  Asheville,  N.  C. 

Orochauite  is  from  Grochau  in  Silesia. 

Cromtedtite.  Hexagonal,  with  perfect  basal  cleavage.  Black.  G.= 
3'35.  Consists  mainly  of  silica,  iron  oxides,  and  water,  with  a  little 
manganese  oxide.  From  Bohemia  and  Cornwall. 

Thuringite.  Another  hydrous  iron  silicate,  having  G.=3'15-3-20, 
from  Thuringia,  and  also  Hot  Springs,  Arkansas,  and  near  Harper's 
Ferry,  on  the  Potomac.  Patter sonite,  from  Union  ville,  Pa.,  is  near  it. 

Margarita.— Emerylite.     Diphanite.     Clingmanite.     Corundellite. 
Trimetric.    Foliated,  mica-like.     Laminae  rather  brittle. 
Color  white,  grayish,  reddish.     Lustre  of  cleavage  surface 


320  DESCRIPTIONS   OP   MINERALS. 

strong  pearly  and  brilliant,  of  sides  of  crystals  vitreous. 
H.=3'5-4-5.  G.  =  2.99. 

Composition.  II2RA12  Oi2Si2= Silica  30*1,  alumina  51.2, 
lime  11  *6,  soda  2-6,  water  4*5  =  100.  B.B.  whitens  and  fuses 
on  the  edges. 

Obs.  Often  associated  with  corundum  and  diaspora.  Oc- 
curs in  Asia  Minor  ;  at  Sterzing  in  the  Tyrol  ;  in  the 
Urals  ;  in  Village  Green,  and  Unionville,  Pa. ;  in  Buncombe 
County,  N".  0.;  at  Chester,  Mass.  Named  from  the  Greek 
margarites,  a  pearl. 

Wittcoxite  is  near  margarite.  Dudleyite  is  an  alteration  product  of 
margarite. 

Chloritoid.— Masonite.     Phyllite.     Ottrelite. 

Monoclinic  or  triclinic.  Cleavage  basal,  perfect.  Also 
coarse  foliated  massive  ;  and  in  thin  disseminated  scales 
(phyllite  or  ottrelite).  Brittle. 

Color  dark  gray,  greenish,  to  black.  Lustre  of  cleavage 
surface  somewhat  pearly. 

Composition.  FeAl  06Si  +  l  aq= Silica  24'0,  alumina  40 '5, 
iron  protoxide  284,  water  7*1  =  100.  B.B.  becomes  darker 
and  magnetic,  but  fuses  with  difficulty.  Decomposed  com- 
pletely by  sulphuric  acid. 

Obs.  Found  at  Kossoibrod,  Urals,  with  cyanite  ;  in  Asia 
Minor,  with  emery;  at  St.  Marcel  ;  Ottrez,  France  (Ottre- 
lite) ;  Chester,  Mass.;  in  Eh  ode  Island  (Masonite)  ;  at 
Brome  and  Leeds,  Canada.  Phyllite  in  scales  character- 
izes the  "  spangled  mica  slate "  of  Newport,  R.  I.,  and 
Sterling,  Goshen,  etc.,  Mass. 

Seybertite.  Occurs  in  somewhat  mica  like,  or  thin  foliated  forms, 
with  perfect  basal  cleavage,  and  laminae  brittle,  the  color  reddish  or 
yellowish  brown  to  copper-red.  Analysis  by  Brush  obtained  Silica  20  24, 
alumina  39 '13,  iron  sesquioxide  3 '27,  magnesia  20*84,  lime  13-69,  water 
1'04,  potash  and  soda  T43,  zirconia  0'75=100'39,  giving  the  quantiva- 
lent  ratio  for  protoxides,  sesquioxides,  silica,  and  water  6  : 9  : 5  :  £.  From 
Amity,  N.  Y. ;  Slatoust,  Urals  (Xanthophyllite) ;  Fassa  Valley  (Bran- 
disite  and  Disterrite). 

IV.  HYDROCARBON  COMPOUNDS. 

The  following  are  the  subdivisions  here  used. 
I.  SIMPLE  HYDKOCABBOHS  :  Marsh-gas,  Mineral  oils,  and 
Mineral  wax. 


SIMPLE   HYDROCARBONS.  321 

II.  OXYGENATED  HYDROCARBONS  :  mostly  resins. 

III.  ASPHALTUM  AND  MINERAL  COALS. 

I.  SIMPLE  HYDROCARBONS. 
Marsh-Gas. — Light  Carburetted  Hydrogen 

Colorless  and  inodorous  gas  in  the  pure  state.  Inflam- 
mable, and  burns  with  a  yellow  flame.  Composition  CII4= 
Carbon  75,  hydrogen  25  —  100. 

Obs.  This  gas  (mixed  with  more  or  less  carbon  dioxide 
and  nitrogen)  often  rises  in  bubbles  through  the  waters  of 
marshes,  whence  its  name  ;  and  frequently  it  is  discharged 
from  fissures  into  coal  mines  in  large  quantities,  constituting 
the  fire-damp  of  the  mine.  Such  natural  discharges,  called 
blowers,  sometimes  continue  for  months.  It  is  the  cause  of 
the  explosions  in  mines,  a  mixture  of  it  with  the  atmo- 
sphere exploding  on  the  approach  of  the  flame  of  a  can- 
dle. It  destroys  life  both  by  the  concussion  occasioned,  by 
the  exhaustion  of  the  atmosphere  of  oxygen,  and  by  the 
production  of  carbon  dioxide  which  takes  place.  The  gas 
which  issues  from  the  oil  springs  or  wells  of  Western  New 
York  (Fredonia),  and  Eastern  Pennsylvania,  is  marsh-gas 
mixed  with  other  vapors  of  the  Marsh-gas  series.  It  is  used 
in  some  places  for  lighting  houses,  and  even  villages  ;  and 
also  for  other  purposes  where  heat  is  required. 

The  gas  bubbling  up  from  a  marsh  in  Europe  afforded 
Websky  Carbon  dioxide  2-97,  marsh-gas  43-36,  nitrogen 
53-67=100.  The  first  of  these  ingredients  is  in  fact  one 
of  the  more  abundant  results  of  decomposition,  whetlter 
vegetable  or  animal ;  and  the  percentage  is  here  small 
because  the  gas  is  soluble  in  water,  and  because  it  readily 
enters  into  combinations  with  the  earthy  ingredients  of 
plants. 

Petroleum. 

Mineral  oils,  varying  in  density  from  0*60  to  0-85.  Solu- 
ble in  benzine  or  camphene.  They  consist  chiefly  of  liquids 
of  the  Naphtha  and  Ethylene  series.  The  composition  of 
the  Naphtha  or  Marsh-gas  series  is  expressed  by  the  general 
formula,  CnH2n  +  2,  of  which  Marsh-gas  is  the  first  or 
lowest  term  ;  and  that  of  the  Ethylene  series  by  the  for- 
mula, CnH2n=rCarbon  85'71,  hydrogen  14-29-100.  The 
oils  vary  greatly  in  density  from  the  lightest  naphtha,  too 


DESCRIPTIONS  OP  MINERALS. 


inflammable  for  use  in  lighting,  to  thick  viscid  fluids  ;  and 
thence  they  pass  by  insensible  gradations  into  asphaltum  or 
solid  bitumen.  The  Marsh-gas  series  contains  also  gases, 
of  the  composition  C2H6  and  C3H8  and  these,  in  addition  to 
Marsh-gas,  often  exist  in  connection  with  petroleum. 

Petroleum  occurs  in  rocks  of  all  ages,  from  the  Lower 
Silurian  to  the  most  recent  ;  in  limestones,  the  more  com- 
pact sandstones,  and  shales  ;  but  it  is  mostly  obtained  from 
large  cavities  or  caverns  existing  among  the  earth's  strata. 
Black  shales  and  much  bituminous  coal  afford  it  abundantly 
when  they  are  heated.  But  the  oil  obtained  is  not  present 
in  these  rocks,  for  when  the  rocks  are  treated  with  benzine, 
the  benzine  takes  up  little  or  none  ;  instead,  the  rocks  con- 
tain an  insoluble  hydrocarbon,  which  yields  the  oil  when 
heat  is  applied. 

In  the  United  States  the  oil,  or  the  hydrocarbon  which 
yields  it,  has  been  observed  in  beds  of  the  Lower  and  Upper 
Silurian,  Devonian,  Carboniferous,  Triassic,  Cretaceous,  and 
Tertiary  eras.  Surface  oil  springs  also  occur  in  many  places, 
as  at  Cuba,  Alleghany  County,  N.  Y.,  called  Seneca  Oil 
Spring  ;  and  on  a  large  scale  in  Santa  Barbara,  Southern 
California  ;  at  Rangoon  in  Burmah,  where  there  are  about 
100  wells  ;  on  the  peninsula  of  Apcheron,  on  the  Caspian, 
and  elsewhere.  Pliny  mentions  the  oil  spring  of  Agrigen- 
tum,  Sicily,  and  says  that  the  liquid  was  collected  and  used 
for  burning  in  lamps,  as  a  substitute  for  oil.  Moreover  he 
distinguishes  the  oil  from  the  lighter  and  more  combustible 
naphtha,  a  locality  of  which  about  the  sources  of  the  Indus, 
^n  Parthia,"  he  mentions. 

Petroleum  is  obtained  chiefly  at  the  present  time  from 
more  or  less  deeply-seated  subterranean  chambers  or  cavities 
among  the  rock  "strata,  reached  by  boring.  Being  under 
pressure  of  gas  associated  with  it,  and  also,  in  many  cases, 
that  also  of  water,  it  rises  to  the  surface  in  the  boring,  and 
sometimes  makes  a  "spouting"  well.  As  early  as  1833, 
Hildreth  mentioned  the  discharge  of  oil  with  the  waters 
of  the  salt  wells  of  the  Little  Kanawha  valley  ;  and  speaks 
also  of  a  well  near  Marietta,  Ohio,  which  threw  out  at  one 
time,  he  says,  50  to  60  gallons  of  oil  at  "  each  eruption." 

The  mineral  oil  of  the  rocks  has  been  formed  through 
the  decomposition  of  animal  and  vegetable  substances. 
From  the  nature  of  the  rocks  which  most  abound  in  the 
species  of  hydrocarbons  that  yield  oil,  it  is  evident  that 


SIMPLE   HYDROCARBONS. 


the  rock  material  was  in  the  state  of  a  fine  mud ;  that 
through  this  mud  much  vegetable  or  animal  matter  was 
distributed,  almost  in  the  condition  of  an  emulsion  ;  that 
the  stratum  of  this  mud  becoming  afterward  overlaid  by 
other  strata,  the  decomposition  of  vegetable  or  animal  mat- 
ter went  forward  without  the  presence  of  atmospheric  air, 
or  with  only  very  little  of  it.  Under  such  circumstances 
either  vegetable  material  or  animal  oils  might  be  converted, 
as  chemists  have  shown,  into  mineral  oil.  Dry  wood  con- 
sists approximately  (excluding  the  ash  and  nitrogen)  of  6 
atoms  of  carbon  to  9  of  hydrogen,  and  4  of  oxygen.  If  now 
all  the  oxygen  of  the  Avood  combines  with  a  part  of  the  car- 
bon to  form  carbonic  acid,  and  this  2  C02,  thus  made,  is  re- 
moved, there  will  be  left  C4 II9 ;  twice  this,  C8  H18,  is  the 
formula  of  a  compound  of  the  Marsh-gas  or  Naphtha  series. 
Again  animal  oils,  by  decomposition  under  similar  cir- 
cumstances, produce  like  results.  Removing  from  oleic 
acid  its  oxygen,  02,  and  1  of  carbon— together  equivalent  to 
1  of  carbonic  acid — there  is  left  C17  H?4,  which  is  an  oil  of 
the  Ethylene  series  ;  and  margaric  acid  would  leave,  in  the 
same  way,  C16  H34,  or  a  combination  of  oils  of  the  Marsh-gas 
or  Naphtha  series.  Warren  and  Storer  have  obtained  from 
the  destructive  distillation  of  a  fish-oil,  after  its  saponifica- 
tion  by  lime,  several  compounds  of  the  Marsh-gas  series,  be- 
sides others  of  the  Ethylene  and  Benzole  series.  The  de- 
compositions in  nature  may  not  have  been  as  simple  as  those 
in  the  above  illustrations,  yet  the  facts  warrant  the  infer- 
ence that  the  oils  may  have  been  derived  either  from  vege- 
table or  animal  matters.  Fossil  fishes  are  often  found  abun- 
dantly in  black  oil-yielding  shales,  and  Dr.  Newberry  has 
suggested  that  fish-oil  may  be  the  most  abundant  source  of 
the  oil  and  the  oil-yielding  hydrocarbons. 

The  oil  which  is  collected  in  great  cavities  among  the 
earth's  strata,  as  in  Western  Pennsylvania,  is  believed  by 
most  writers  on  the  subject  to  have  come  from  underlying 
rocks,  such  as  the  black  oil-yielding  shales.  The  heat  pro- 
duced in  the  rocks  by  the  friction  attending  movements  and 
uplifts,  is  supposed  to  have  been  sufficient  to  have  made  the 
oil  from  the  hydrocarbon  of  the  carbonaceous  shale  or  other 
rock,  and  co  have  caused  it  to  ascend  among  the  strata  to 
the  cavities  where  it  was  condensed,  and  now  is  found  by 
boring. 

The  oils,  exposed  to  the  air  and  wind, undergo  change  in 


324  DESCRIPTIONS   OF   MINERALS. 

three  ways.  First :  the  lighter  naphthas  evaporate,  leaving 
the  denser  oils  behind  ;  and,  ultimately,  the  viscid  bitumens, 
or  else  paraffin,  according  as  paraffin  is  present  or  not  in 
the  native  oil.  At  the  naphtha  island  of  Tschelekan  in  Per- 
sia, there  are  large  quantities  of  Neft-yil,  as  it  is  called, 
which  is  nearly  pure  paraffin.  The  hot  climate  of  the  Cas- 
pian is  favorable  for  such  a  result.  Secondly:  ther  emay 
be  a  loss  of  hydrogen  from  its  combination  with  the  oxygen 
of  the  atmosphere  to  form  water,  which  escapes.  Thus  the 
oils  of  the  Naphtha  series  may  change  into  those  of  the  Ethy- 
lene  or  Benzole  series.  Thirdly :  there  may  be  an  oxidation 
of  the  hydrocarbon  of  the  oils,  producing  asphaltum  or 
more  coal-like  substances,  like  albertite. 

The  word  naphtha  is  from  the  Persian,  nafata,  to  exude  ; 
and  petroleum  from  the  Greek,  petros,  rock,  and  the  Latin, 
oleum,  oil. 

Hachettite.— Mountain  Tallow,     Hatchetine. 

Like  soft  wax  in  appearance  and  hardness,  of  a  yellowish- 
white  to  greenish -yellow  color. 
Composition.    Related  to  paraffin. 
From  the  coal-measures  of  Glamorganshire  in  Wales. 

Ozocerite  is  like  wax  or  spermaceti  in  consistence.  Soluble  in  ether. 
The  original  was  from  Moldavia.  Along  with  another  wax -like  sub- 
stance, called  Urpethite,  it  constitutes  trie  "mineral  wax  of  Urpeth 
Colliery."  Zietrisikite  is  like  beeswax,  and  is  insoluble  in  ether ; 
from  Moldavia, 


Elaterite. — Mineral  Caoutchouc.     Elastic  Bitumen. 

In  soft  flexible  masses,  somewhat  resembling  caoutchouc 
or  India  rubber.  Color  brownish-black  ;  sometimes  orange- 
red  by  transmitted  light.  G.  =0'9-r25.  Composition:  Car- 
bon 85*5,  hydrogen  13  '3  =  98  -8.  It  burns  readily  with  a  yel- 
low flame  and  bituminous  odor. 

Obs.  From  a  lead  mine  in  Derbyshire,  England,  and  a 
coal  mine  at  Montrelais.  It  has  been  found  at  Woodbury, 
Ct.,  in  a  bituminous  limestone. 

Fichtelite  and  Hartite  are  crystallized  hydrocarbons,  of  the  Cam- 
phene  series.  Branchite,  Dinite,  and  Ixolyte  are  related  to  Hartite. 
Konlite,  Naphthalin,  and  Idrialite  are  native  species  of  the  Benzole 
series.  Aragotite,  from  California,  is  near  Idrialite. 


OXYGENATED  HYDROCARBONS.  325 

II.  OXYGENATED  HYDROCARBONS. 
Amber. 

In  irregular  masses.  Color  yellow,  sometimes  brownish 
or  whitish  ;  lustre  resinous.  Transparent  to  translucent. 
H.  =  2-2-o.  G.=  l-18.  Electric  by  friction. 

Amber  is  not  a  simple  resin,  but  consists  mainly  (85  to  90 
percent.)  of  a  resin  which  resists  all  solvents,  called  Suc- 
cinite, and  two  other  resins  soluble  in  alcohol  and  ether, 
besides  an  oil,  and  2%  to  G  per  cent,  of  Succinic  acid. 

Obs.  Occurs  in  the  loose  deposits  along  coasts,  especially 
Tertiary  strata,  in  masses  from  a  very  small  size  to  that  of 
a  man's  head.  In  the  Koyal  Museum  at  Berlin,  there  is  a 
mass  weighing  18  pounds.  On  the  Baltic  coast  it  is  most 
abundant,  especially  between  Konigsberg  and  Memel.  It 
is  met  with  at  one  place  in  a  bed  of  bituminous  coal ;  it 
also  occurs  on  the  Adriatic  ;  in  Poland  ;  on  the  Sicilian 
coast  near  Catania  ;  in  France  near  Paris,  in  clay ;  in  China. 
It  has  been  found  in  the  United  States,  at  Gay  Head, 
Martha's  Vineyard  ;  Camden,  N.  J.  ;  and  at  Cape  Sable, 
near  the  Magothy  River,  in  Maryland. 

It  is  supposed,  with  good  reason,  to  be  a  vegetable  resin 
which  has  undergone  some  change  while  inhumed,  a  part 
of  which  is  due  to  acids  of  sulphur  proceeding  from  decom- 
posing pyrites  or  some  other  source.  It  often  contains  in- 
sects, and  specimens  of  this  kind  are  so  highly  prized  as 
frequently  to  be  imitated  for  the  shops.  Some  of  the  insects 
appear  evidently  to  have  struggled  after  being  entangled  in 
the  then  viscous  resin,  and  occasionally  a  leg  or  a  wing  is 
found  some  distance  from  the  body,  having  been  detached 
in  the  struggle  for  escape. 

Amber  is  the  electron  of  the  Greeks  ;  from  its  becoming 
electric  so  readily  Avhen  rubbed,  it  gave  the  name  electricity 
to  science.  It  was  also  called  succinum,  from  the  Greek 
succum,  juice,  because  of  its  supposed  vegetable  origin. 

It  admits  of  a  good  polish  and  is  used  for  ornamental 
purposes,  though  not  very  much  esteemed,  as  it  is  wanting 
in  hardness  and  brilliancy  of  lustre,  and  moreover  is  easily 
imitated.  It  is  much  valued  in  Turkey  for  mouth-pieces 
to  pipes. 

Copalite,  or  Mineral  Copal,  Walchowite,  Ambrite  (the  New  Zealand 
resin),  Euosmite,  Scleretinite,  Middletote  are  some  of  the  names  of 
other  fossil  resins  ;  Geocerite,  and  Geomyricite,  of  wax -like  oxygenated 
species  ;  Guyaquittite,  BathvUlite,  Torbanite,  lonite  (from  lone  valley, 


326  DESCRIPTIONS   OF   MINERALS. 

California),  of  species  not  resinous  in  lustre  ;  Tasmanite  and  Dysodile, 
of  kinds  containing  several  per  cent,  of  sulphur.  Wollongongite,  from 
Australia,  is  black,  and  looks  like  cannel  coal. 

III.  ASPHALTUM  AND  MINERAL  COALS. 
Asphaltum. 

Amorphous  and  pitch-like.  Burning  with  a  bright  flame 
and  melting  at  90°  to  100°  F.  Soluble  mostly  or  wholly  in 
camphene.  It  is  a  mixture  of  hydrocarbons,  part  of  which 
are  oxygenated. 

Obs.  Asphaltum  is  met  with  abundantly  on  the  shores  of 
the  Dead  Sea,  and  in  the  neighborhood  of  the  Caspian.  A 
remarkable  locality  occurs  on  the  island  of  Trinidad,  where 
there  is  a  lake  of  it  about  a  mile  and  half  in  circumference. 
The  bitumen  is  solid  and  cold  near  the  shores;  but  gradu- 
ally increases  in  temperature  and  softness  toward  the  cen- 
tre, where  it  is  boiling.  The  appearance  of  the  solidified 
bitumen  is  as  if  the  whole  surface  had  boiled  up  in  large 
bubbles  and  then  suddenly  cooled.  The  ascent  to  the  lake 
from  the  sea,  a  distance  of  three  quarters  of  a  mile,  is  cov- 
ered with  the  hardened  pitch,  on  which  trees  and  vegetation 
flourish,  and  here  and  there,  about  Point  La  Braye,  the 
masses  of  pitch  look  like  black  rocks  among  the  foliage.  It 
occurs  also  in  South  America  about  similar  lakes  in  Peru, 
where  it  is  used  for  pitching  boats  ;  and  in  California  on 
the  coast  of  Santa  Barbara.  Large  deposits  occur  in  sand- 
stone in  Albania.  It  is  also  found  in  Derbyshire,  and  with 
quartz  and  fluor  in  granite  in  Cornwall,  and  at  many  other 
places. 

Albertite. 

Coal-like  in  hardness,  but  little  soluble  in  camphene,  and 
only  imperfectly  fusing  when  heated  ;  but  having  the  lustre 
of  asphaltum,  and  softens  a  little  in  boiling  water.  H.  —  1-2. 
G.=  1-097. 

Fills  fissures  in  the  Subcarboniferous  rocks  near  Hills- 
borough,  Nova  Scotia,  and  supposed  to  have  been  derived 
from  the  hydrocarbon  of  the  adjoining  rock,  and  to  have 
been  oxidized  at  the  time  it  was  formed  and  filled  the 
fissure. 

Orahamite  is  a  related  material  from  West  Virginia,  20  miles  south 
of  Parkersburg.  ^H.  =2.  G.  ^t'143.  Soluble  mostly  in  camphene, 
but  melts  only  imperfectly.  An  analysis  afforded  carbon  76 '45,  hy- 
drogen 7 '82,  oxygen  (with  traces  of  nitrogen)  13 '40,  ash  2 '26 =100, 


MINERAL   COAL.  327 

MINERAL  COAL. 

Massive.  Color  black  or  brown  ;  opaque.  Brittle  or  im- 
perfectly sectile.  H.  =0-5-2-5.  G.  =  1  '2-1-80. 

Composition.  Carbon,  with  some  oxygen  and  hydrogen, 
more  or  less  moisture,  and  traces  also  of  nitrogen,  besides 
some  earthy  mineral  which  constitutes  the  ash.  The  car- 
bon, or  part  of  it,  is  in  chemical  combination  with  the 
hydrogen  and  oxygen. 

Coals  differ  in  the  amount  of  volatile  ingredients  given 
off  when  heated.  These  ingredients  are  moisture,  and  hy- 
drocarbon oils  and  gas,  derived  from  the  same  class  of 
insoluble  hydrocarbons  that  is  the  source  of  the  oil  of  shales 
and  other  rocks. 


VARIETIES. 


1.  Anthracite.     Anthracite  (called   also  (/lance  coal  and 
stone  coal)  has  a  high  lustre,  and  is  often  iridescent.     It  is 
quite  compact  and  hard,  and  has  a  specific  gravity  from  1'3 
to  1*75.     It  usually  contains  80  to  93  per  cent,  of  carbon, 
with  4  to  7  of  volatile  matter  ;  the  rest  consisting  of  earthy 
impurities.     Burns  with  a  feeble  blue  flame. 

Those  yielding  the  most  volatile  ingredients  are  called 
free-burning  anthracite. 

2.  Bituminous  Coal.    Bituminous  coal  varies  much  in  the 
amount  of  oil,  coal-tar,  or  gas  it  yields  when  heated;  and 
there  is  a  gradual  passage  in  its  varieties  through  semi- 
anthracite  to  anthracite.     It  is  of  a  black  color,  with  the 
powder  black,  but  it  is  softer  than   anthracite,  and  less 
lustrous.     The  specific  gravity  does  not  exceed  1*5.     The 
volatile  ingredients  constitute  usually  between  20  and  40 
per  cent. 

Caking  Coal  includes  that  part  of  bituminous  coal  which 
softens  when  heated  and  becomes  viscid,  so  that  adjoining 
pieces  unite  into  a  solid  mass.  It  burns  readily  with  a 
lively  yellow  flame,  but  requires  frequent  stirring  to  prevent 
its  agglutinating,  and  so  clogging  the  fire.  Non-caking  coal 
resembles  the  caking  in  appearance,  but  does  not  soften  and 
cake.  The  chemical  difference  between  caking  and  non- 
caking  coal  is  not  understood. 

3.  Cannel  Coal  is  very  compact  and  even  in  texture,  with 
little  lustre,  and  breaks  with  a  large  conchoidal  fracture.  It 
takes  fire  readily,  and  burns  without  melting  to  a  clear  yel- 


328  DESCRIPTIONS   OP   MINERALS. 

low  flame,  and  has  hence  been  used  as  candles — whence  the 
name.  It  affords  when  heated  a  large  amount  of  mineral 
oil,  and  may  be  used  for  its  production.  The  volatile  in- 
gredients sometimes  amount  to  50  or  60  per  cent.  It  is 
often  made  into  inkstands,  snuff-boxes,  and  other  similar 
articles. 

4.  Brown  Coal  usually  has  a  brownish-black  color,  and 
contains  15  to  20  per  cent,  of  oxygen,  but  much  resembles 
in  appearance  bituminous  coal.  The  term  brown  coal  is  ap- 
plied generally  to  any  coal  more  recent  in  origin  than  the 
era  of  the  great  coal  beds  of  the  world.  The  name  lignite 
has  sometimes  the  same  general  application,  though  without 
strict  propriety.  Lignite  is  the  part  of  brown  coal  which 
has  the  woody  structure  still  apparent. 

Jet  resembles  cannel  coal,  but  is  harder,  of  a  deeper  black 
color,  and  has  a  much  higher  lustre.  It  receives  a  brilliant 
polish,  and  is  set  in  jewelry.  It  is  the  Gagates  of  Diosco- 
rides  and  Pliny,  a  name  derived  from  the  river  Gagas,  in 
Syria,  near  the  mouth  of  which  it  was  found,  and  the  origin 
of  the  term  jet  now  in  use. 

Native  Coke  resembles  somewhat  artificial  coke,  but  is 
more  compact,  and  some  varieties  of  it  afford  a  consider- 
able amount  of  bitumen.  It  occurs  at  the  Edgehill  mines 
near  Richmond,  Virginia,  according  to  Genth,  who  attri- 
butes its  origin  to  the  action  of  a  trap  eruption  on  bitumi- 
nous coal. 

It  is  now  well  established  that  mineral  coal  is  mainly  of 
vegetable  origin,  and  that  the  accumulations  out  of  which 
the  coal  beds  were  made  were  very  similar  in  character, 
though  not  in  kinds  of  plants,  to  the  peat  beds  of  the  pres- 
ent day.  Peat  is  vegetation  which  has  undergone,  in  part, 
the  change  to  coal ;  and  in  some  cases  it  has  become  brown 
coal.  The  conditions  of  change  are  somewhat  different  from 
those  of  the  beds  of  good  coal,  since,  in  the  case  of  the  peat, 
the  air  has  access,  while  in  that  of  the  coal  the  air  was  more 
or  less  excluded  by  overlying  strata  ;  and  the  more  perfect 
the  exclusion,  other  things  equal,  the  better  the  coal.  As 
the  composition  of  mineral  coal  is  closely  related  to  that  of 
mineral  oils",  the  explanation  of  the  origin  of  the  latter,  given 
on  page  323,  suffices  to  illustrate  also  the  origin  of  the 
former.  With  a  less  complete  exclusion  of  the  air,  oxygen- 
ated hydrocarbon  compounds,  like  coal,  would  be  a  natural 
result. 


MINERAL   COAL. 


329 


The  following  are   a  few  analyses  of  coals,  the  moisture 
excluded: 


Carbon. 

Hydr. 

Oxyg. 

Nitr. 

Sulph. 

Ash. 

1 

Anthracite    Pennsylvania 

90  45 

2-43 

2-45 

4-67 

0, 

Anthracite    Pennsylvania 

92  59 

263 

1-61 

092 

225 

3 

Anthracite,  South  Wales  .  . 

92  56 

3  33 

2-53 

1  58 

4 
5 
6 

7 
8 

Caking  Coal,  Kentucky  
Caking  Coal,  Nelsonville,  O. 
Caking  Coal,  South  Wales.  . 
Caking  Coal,  Northumberl'd 
Non-caking,  Kentucky  

74-45 
73-80 
82-56 
78'69 
77-89 

4-93 
579 
536 
6-00 
5  42 

1308 
16-58 
8-22 
10-07 
12-57 

103 
1-52 
1-65 
2-37 

1-82 

091 
0-41 
075 
1-51 
3-00 

500 
190 
1-46 
1-36 
200 

9 

Non-caking  "  Black  Coal,"  ) 
Ind                    ) 

82-70 

4-77 

939 

1-62 

0-45 

1-07 

10 
11 
19 

Non-caking,  Briar  Hill,  O.  . 
Non-caking,  S.  Staffordshire 
Non-cakin0"   Scotland     .    .  . 

78-94 
7640 
76'08 

5-92 
462 
5  -81 

11-50 
17-43 
13  33 

1-58 
209 

0-56 
0-55 
1-23 

1-45 
155 
1-96 

13 
14 

Cannel  Coal,  Breckenridge  . 
Cannel  Coal   ^^igan 

68-13 
8007 

6-49 
5  53 

5-83 
8  10 

2-27 
2-12 

2-48 
1-50 

1230 
2-70 

15 
16 

Cannel  Coal,  "  Torbanite". 
Albertite   Nova  Scotia 

6402 
86*04 

8-90 
8  '96 

5-66 
1-97 

055 
293 

050 
tTace 

2032 

o-io 

17 

Brown  Coal  Bovey 

66-31 

5  63 

22-86 

0-57 

2-36 

2-27 

is 

Brown  Coal  Wittenberg.  .  . 

64-07 

503 

27-55 

335 

19 

Peat  light  brown  (imperfect) 

50'86 

5  -80 

42-57 

0*77 

30 

Peat  dark  bcown 

59-47 

6-52 

31  51 

2  51 

?r1 

Peat    black  

59-70 

5-70 

3304 

1  56 

00, 

Peat    black 

59-71 

5  27 

32-07 

2-59 

The  coal,  No.  4,  from  "Roberts'  Seam,"  Muhlenburg  County,  Ken- 
tucky, has  specific  gravity =1  26  ;  No.  9,  from  "  Wolf  Hill,"  Daviess 
County,  Indiana,  has  specific  gravity =1  "275. 

No.  13,  the  Breckenridge  cannel,  of  Hancock  County,  Kentucky, 
consists,  when  the  ash  is  excluded,  of  Carbon  82 '36,  hydrogen  7 '84, 
oxygen  7  05,  nitrogen  2  75,  and  the  Bog-head  cannel  of  Scotland,  called 
also  torbanite,  contains  Carbon  8039,  hydrogen  11-19,  oxygen  7 '11,  ni 
trogen  1*31. 

The  "  Mineral  Charcoal "  of  coal  beds  differs  little  in  composition 
from  ordinary  bituminous  coal  ;  there  is  less  hydrogen  and  oxygen. 
Rowney  obtained,  for  that  of  Glasgow  and  Fifeshire,  Carbon  82  "97, 
74-71  ;  hydrogen  3  34,  2  74;  oxygen  759,  767  ;  ash  6'08,  I486.  The 
nitrogen  is  included  with  the  oxygen  ;  it  was  0'75  in  the  Glasgow  char- 
coal. Exclusive  of  the  ash,  the  composition  is  Carbon  88/36,  87*78  ; 
hydrogen  356,  321;  oxygen  7 '28,  9' 01.  It  has  a  fibrous  look,  and 
occurs  covering  the  surfaces  between  layers  of  coal,  and  has  been  ob- 
served in  coal  of  all  ages.  It  is  soft  and  soils  the  fingers  like  char- 
coal ;  one  variety  of  it  is  a  dry  powder. 


330  DESCRIPTIONS   OF   MINERALS. 

The  following  are  average  results,  from  many  analyses  : 


Vol. 

Fixed 

Nos. 

Sp.  gr. 

com- 

Car- 

Ash. 

Analysis. 

bust. 

bon. 

1 

Pennsylvania  anthracites.  .  .  -j 

7 
16 

1-59-1-61 
1-39-1  -GO 

3-92 
5-70 

89-77 
88-23 

6-31 

6-07 

Johnson. 
Geol.  Survey. 

2 

Pennsylvania    semi-anthra-  1 
cites                                     f 

11 

1-33-1-45 

9-98 

82-86 

7-16 

Geol.  Survey. 

3 

Pennsylvania  semi-bitunii-  1 
nous       .        f 

6 

1-30-1-41 

16-85 

72-95 

10-20 

Johnson. 

4 

Maryland  semi-bituminous... 

9 

1-30-1-43 

1550 

7403 

10-47 

(  Johnson  and 
j  Geol.  Survey. 

5 

Pennsylvania  bituminous  

10 

28-35 

65-18 

6-47 

Johnson. 

6 

Virginia  bituminous     .   .   . 

11 

i  29-1-45 

29'88 

59-06 

11-06 

Johnson. 

7 

Ohio  bituminous  

142 

1-24-1-47 

35-24 

60-26 

4-50 

Wormley. 

g 

126  1'1Q  1'41 

43-20 

53-47 

3'33 

Cox 

q 

Illinois  bituminous  .  .  . 

50 

1-21  1-35 

31  90 

62-44 

5'66 

Blaney. 

10 

Iowa  bituminous       .        ... 

59 

43-02 

6-82 

Emery. 

The  ordinary  impurities  of  coal,  making  up  its  ash,  are  silica,  a 
little  potash  and  soda,  and  sometimes  alumina,  with  often  oxide  of 
iron,  derived  usually  from  sulphide  of  iron  ;  besides,  in  the  less  pure 
kinds,  more  or  less  clay  or  shale.  The  amount  of  ash  does  not  ordina- 
rily exceed  6  per  cent.,  but  it  is  sometimes  80  per  cent. ;  and  rarely  it 
is  less  than  2  per  cent.  When  not  over  3  or  4  per  cent,  the  whole  may 
have  come  from  the  plants  which  contributed  the  most  of  the  material 
of  the  coal,  since  the  Lycopods  have  much  alumina  in  the  ash,  and 
the  Equiseta  much  silica. 

There  is  present  in  most  coal  traces  of  sulphide  of  iron  (pyrite),  suf- 
ficient to  give  sulphur  fumes  to  the  gases  from  the  burning  coal,  and 
sometimes  enough  to  make  the  coal  valueless  in  metallurgical  opera- 
tions. Some  thin  layers  are  occasionally  full  of  concretionary  pyrite. 
The  sulphur  was  derived  from  the  plants  or  from  animal  life  in  the 
waters.  Sulphur  also  occurs,  in  some  coal  beds,  as  a  constituent  of  a 
resinous  substance  ;  and  Wormley  has  shown  that  part  of  the  sulphur 
in  the  Ohio  coals  is  in  some  analogous  state,  there  being  not  iron 
enough  present  to  take  the  whole  into  combination. 

The  average  amount  of  ash  in  eighty-eight  coals  from  the  southern 
half  of  Ohio,  according  to  Wormley,  is  4'718  per  cent.;  in  sixty-six 
coals  from  the  northern  half,  5 '120  ;  in  all,  from  both  regions,  4 '891 ; 
or,  omitting  ten,  having  more  than  ten  per  cent,  of  ash,  the  average  is 
4"->8.  In  eleven  Ohio  cannels,  the  average  amount  of  ash  was  12'827. 
The  moisture  in  the  Ohio  coals,  according  to  the  analyses  of  Wormley, 
varies  from  T10  to  910  per  cent,  of  the  coal. 

Mineral  coal  occurs  in  extensive  beds  or  layers,  interstratified  with 
different  rock  strata.  The  associate  rocks  are  usually  clay  shales  (or 
slaty  beds)  and  sandstones  ;  and  the  sandstones  are  occasionally  coarse 
grit  rocks  or  conglomerates.  There  are  sometimes  also  beds  of  lime- 
stone alternating  with  the  other  deposits. 

Coal  beds  vary  in  thickness  from  a  fraction  of  an  inch  to  40  feet. 
The  thickness  of  a  bed  may  increase  or  diminish  much  in  the  course 
of  a  few  miles,  or  the  coalmay  become  too  shaly  to  work. 


MINERAL   COAL.  331 

The  areas  of  the  "coal-measures"  of  the  Carboniferous  era,  in 
the  United  States,  are  as  follows  : 

1.  A  small  area  in  Rhode  Island,  continued  northward  into  Massa- 
chusetts. 

2.  A  large  area  in  Nova  Scotia  and  New  Brunswick,  stretching  east- 
ward and  westward  from  the  head  of  the  Bay  of  Fundy. 

These  two  areas  are  now  separated  ;  but  it  is  probable  that  they 
were  once  united  along  the  region,  now  submerged,  of  the  Bay  of 
Fundy  and  Massachusetts  Bay. 

3.  The  Alleghany  Region,  which  commences  at  the  north  on  the 
southern  borders  of  New  York,  and  stretches  south  westward  across 
Pennsylvania,  West  Virginia,  and  Tennessee  to  Alabama,  and  west- 
ward over  part  of  Eastern  Ohio,  Kentucky,  Tennessee,  and  a  small 
portion   of  Mississippi.     To  the  north,  the   Cincinnati  "  uplift,"  or 
the  Silurian  area  extending  from  Lake  Erie  over  Cincinnati  to  Ten- 
nessee, forms  the  western  boundary. 

4.  The  Michigan  coal  area,  an  isolated  area  wholly  confined  within 
the  lower  peninsula  of  Michigan. 

5.  The  Eastern  Interior  area,  covering  nearly  two-thirds  of  Illinois, 
and  parts  of  Indiana  and  Kentucky. 

6.  The  Western  Interior  area,  covering  a  large  part  of  Missouri, 
and  extending  north  into  Iowa,  and  South,  with  interruptions,  through 
Arkansas  into  Texas,  and  west  into  Kansas  and  Nebraska. 

The  Illinois  and  Missouri  areas  are  connected  now  only  through  the 
underlying  Subcarbonif erous  rocks  of  the  age  ;  but  it  is  probable  that 
formerly  the  coal  fields  stretched  across  the  channel  of  the  Missis- 
sippi, and  that  the  present  separation  is  due  to  erosion  along  the 
valley.  Rocks  of  the  Carboniferous  period  extend  over  large  portions 
of  the  Rocky  Mountain  area,  but  they  are  mostly  limestones,  and  are 
barren  of  coal. 

The  extent  of  the  coal -bearing  area  of  these  Carboniferous  regions 
is  approximately  as  follows  : 

Rhode  Island  area 500  square  miles. 

Alleghany  area 59,000  square  miles. 

Michigan  area 6,700  square  miles. 

Illinois,  Indiana,  West  Kentucky 47,000  square  miles. 

Missouri,  Iowa,  Kansas,  Arkansas,  Texas  78,000  square  miles. 
Nova  Scotia  and  New  Brunswick 18,000  square  miles. 

The  whole  area  in  the  United  States  is  over  190,000  square  miles, 
and  in  North  America  about  208,000.  Of  the  190,000  square  miles, 
perhaps  120,000  have  workable  beds  of  coal. 

Anthracite  is  the  coal  of  Rhode  Island,  and  of  the  areas  in  Central 
Pennsylvania,  from  the  Pottsville  or  Schuylkill  coal  field  to  the  Lacka- 
wanna  field,  while  the  coal  of  Pittsburg,  and  of  all  the  great  coal- 
fields of  the  Interior  basin,  is  bituminous,  excepting  a  small  area  in 
Arkansas.  Anthracite  belongs  especially  to  regions  of  upturned 
rocks,  and  bituminous  coal  to  those  where  the  beds  are  little  disturbed. 
In  the  area  between  the  anthracite  region  of  Central  Pennsylvania 
and  the  bituminous  of  Western,  and  farther  south,  the  coal  is  semi- 
bituminous,  as  in  Broad  Top,  Pennsylvania,  and  the  Cumberland  coal 
field  in  Western  Maryland,  the  volatile  matters  yielded  by  it  being  15 


332  DESCRIPTIONS   OP  MINERALS. 

to  20  per  cent.  The  more  western  parts  of  the  anthracite  coal  fields 
afford  the  free-burning  anthracite,  or  semi-anthracite,  as  at  Trevor- 
ton,  Shamokin,  and  Birch  Creek. 

The  coal-formation  of  the  Carboniferous  age  in  Europe  has  great 
thickness  of  rocks  and  coal  in  Great  Britain,  much  less  in  Spain, 
France,  and  Germany,  and  a  large  surface,  with  little  thickness  of 
coal,  in  Russia.  It  exists,  also,  and  includes  workable  coal-beds,  in 
China,  and  also  in  India  and  Australia  ;  but  part  of  the  formation  in 
these  latter  regions  may  prove  to  be  Permian.  No  coal  of  this  era  has 
yet  been  found  in  South  America,  Africa,  or  Asiatic  Russia.  The  pro- 
portion  of  coal  beds  to  area  in  different  parts  of  Europe  has  teen 
stated  as  follows  :  in  France,  l-100th  of  the  surface  ;  in  Spain,  l-50th; 
in  Belgium,  l-20th  ;  in  Great  Britain,  1-lOth.  But,  while  the  coal 
area  in  Great  Britain  is  about  12,000  square  miles,  that  of  Spain  is 
4,000,  that  of  France  about  2,000,  and  that  of  Belgium  518. 

Mineral  coal  of  later  age  than  the  true  Carboniferous  era  occurs  in 
various  parts  of  the  world.  Triassic  or  Jurassic  coal,  of  the  bitumi- 
nous variety,  occurs  in  thick  workable  beds  in  the  vicinity  of  Rich- 
mond, Virginia,  and  also  in  the  Deep  River  and  Dan  River  regions 
in  North  Carolina  ;  and  it  constitutes  very  valuable  and  extensive 
beds  also  in  India.  In  England,  at  Brora  in  Sutherlandshire,  there 
is  a  bed  of  Jurassic  coal.  Coal  of  the  Cretaceous  and  Tertiary  eras 
constitutes  important  beds  in  various  parts  of  the  Rocky  Mountain 
region,  in  the  vicinity  of  the  Pacific  Railroad  and  elsewhere.  Some 
of  the  prominent  localities  are  :  In  Utah,  at  Evanston  and  Coalville 
(in  the  valley  of  Weber  River),  etc.;  in  Wyoming,  at  Carbon,  140 
miles  from  Cheyenne  ;  at  Hallville,  142  miles  farther  west  ;  at  Black 
Butte  Station,  on  Bitter  Creek  ;  on  Bear  River,  etc. ;  in  the  Uintah 
Basin,  near  Brush  Creek,  6  miles  from  Green  River ;  in  Colorado,  at 
Golden  City,  15  miles  west  of  Denver,  on  Ralston  Creek,  Coal  Creek, 
S.  Boulder  Creek  and  elsewhere  ;  in  New  Mexico,  at  the  Old  Placer 
Mines  in  the  San  Lazaro  Mountains,  etc.  The  coal  is  of  the  bitumi- 
nous or  semibituminous  kind,  related  to  brown  coal,  and  is  often  im 
properly  called  lignite.  That  of  Evanston  (where  the  bed  is  26  feet 
thick)  afforded  Prof.  P.  Frazier,  Jr. ,  37-38  per  cent,  of  volatile  sub- 
stances, 5-6  of  water,  7-8  of  ash,  and  49-50  of  fixed  carbon.  At  the 
Old  Placer  Mines,  New  Mexico,  there  is  anthracite,  according  to  Dr. 
J.  LeConte,  affording  88  to  91  per  cent,  of  fixed  carbon  ;  specimens 
from  there,  analyzed  by  Frazier,  were  semibituminous,  affording 
68-70  per  cent,  of  fixed  carbon,  20  per  cent,  of  volatile  substances,  and 
about  3  per  cent,  of  water.  The  region  of  the  Old  Placer  Mines  is  one 
of  upturned  and  altered  rocks,  like  the  anthracite  region  of  Pennsyl- 
vania. Other  similar  beds  occur  toward  the  Pacific  coast,  the  most 
valuable  of  them  in  Washington  Territory,  Seattle  and  Belli ngham 
Bay,  and  on  Vancouver  and  adjacent  islands  in  British  Columbia. 


CATALOGUE   OF   AMERICAN  LOCALITIES   OF  MINERALS.          333 


I.   CATALOGUE  OP  AMERICAN  LOCALL 
TIES  OF  MINERALS. 

THE  following  catalogue  of  American  localities  of  minerals  is  intro- 
duced as  a  Supplement  to  the  Descriptions  of  Minerals.  Its  object  is 
to  aid  the  mineralogical  tourist  in  selecting  his  routes  and  arranging 
the  plan  of  his  journeys.  Only  important  localities,  affording  cabinet 
specimens,  are  in  general  included  ;  and  the  names  of  those  miner  ah 
which  are  obtainable  in  good  specimens  are  distinguished  by  italics. 
When  a  name  is  not  italicized  the  mineral  occurs  only  sparingly  or  of 
poor  quality.  When  the  specimens  to  be  procured  are  remarkably 
good,  an  e'xclamation  mark  (!)  is  added,  or  two  of  those  marks  (I !) 
when  the  specimens  are  quite  unique. 

MAINE. 

ALBANY. — Beryl!  green  and  black  tourmaline,  feldspar,  rose  quartz, 
rutile. 

AROOSTOOK. — Red  hematite. 

AUBURN. — Lepidolite,  hebronite,  green  tourmaline. 

BATH. — Vesuvianite,  garnet,  magnetite,  graphite. 

BETHEL. — Cinnamon  garnet,  calcite,  sphene,  beryl,  pyroxene,  horn- 
blende, epidote,  graphite,  talc,  pyrite,  arsenopyrite,  magnetite,  wad. 

BINGHAM. — Massive  pyrite,  galenite,  blende,  andalusite. 

BLUE  HILL  BAY. — Arsenical  iron,  molybdenite!  galenite,  apatite! 
fluoritef  black  tourmaline  (Long  Cove),  black  oxide  of  manganese 
(Osgood's  farm),  rhodonite,  bog  manganese,  wolframite. 

BOWDOIN. — Rose  quartz. 

BOWDOINHAM. — Beryl,  molybdenite. 

BRUNSWICK. — Green  mica,  garnet !  black  tourmaline  !  molybdenite, 
epidote,  calcite,  muscomte,  feldspar,  beryl. 

BUCKFIELD.— Garnet  (estates  of  Waterman  and  Lowe),  muscomte! 
tourmaline  !  magnetite. 

CAMDAGE  FARM. — (Near  the  tide  mills),  molybdenite,  wolframite. 

CAMDEN. — Macle,  galenite,  epidote,  black  tourmaline,  pyrite,  talc, 
magnetite. 

CARMEL  (Penobscot  Co.) — Stibnite,  pyrite,  made. 

CORINN A.  — Pyrite,  arsenopyrite. 

DEER  ISLE. — Serpentine,  verd-antique,  asbestus,  diallage. 

DEXTER. — Galenite,  pyrite,  blende,  chalcopyrite,  green  talc. 

DIXFIELD. — Native  copperas,  graphite. 

EAST  WOODSTOCK. — Muscovite. 

FARMINGTON. — (Norton's  Ledge),  pyrite,  graphite,  garnet,  staurolite. 

FREEPORT. — Rose  quartz,  garnet,  feldspar,  scapolite,  graphite,  mu* 
tovite. 

FRYEBURG.— Garnet,  beryl. 

GEORGETOWN.— (Parker's  Island),  beryl!  black  tourmaline. 


334  SUPPLEMENT   TO   DESCRIPTIONSJOF   SPECIES. 

GREENWOOD. — Graphite,  black  manganese,  "beryl!  arsenopyrite, 
cassiterite,  mica,  rose  quartz,  garnet,  corundum,  albite,  zircon,  molyb- 
denite, magnetite,  copperas. 

HEBRON. — Cassiterite,  arsenopyrite,  idocrase,  lepidolite,  hebronite, 
rubellite !  indicolite,  green  tourmaline,  mica,  beryl,  apatite,  albite,  chil- 
drenite,  cookeite. 

JEWELL'S  ISLAND. — Pyrite. 

KATAHDIN  IRON  WORKS. — Bog-iron  ore,  pyrite,  magnetite,  quartz. 

LITCHFIELD. — Sodalite,  cancrinite,  elceolite,  zircon,  spodumene,  mus- 
covite,  pyrrliotite. 

LUBEC  LEAD  MINES. — Galenite,  cJialcopyrite,  blende. 

MACHIASPORT. — Jasper,  epidote,  laumontite. 

MADAWASKA  SETTLEMENTS. —  Vivianite. 

MINOT.  — Beryl,  smoky  quartz. 

MONMOUTH. — Actinolite,  apatite,  elceolite,  zircon,  staurolite,  plumose 
mica,  beryl,  rutile. 

MT.  ABRAHAM. — Andalusite,  staurolite. 

NORWAY. — Chrysoberyl!  molybdenite,  beryl,  rose  quartz,  orthoclase, 
cinnamon  garnet. 

ORR'S  ISLAND. — Steatite,  garnet,  andalusite. 

OXFORD. — Garnet,  beryl,  apatite,  wad,  zircon,  muscovite,  orthoclase. 

PARIS. — Green!  red!  black,  and  blue  tourmaline!  mica!  lepidolite! 
feldspar,  albite,  quartz  crystals!  rose  quartz,  cassiterite,  amblygonite, 
zircon,  brookite,  beryl,  smoky  quartz,  spodumene,  cookeite,  leucopy- 
rite. 

PARSONSFIELD. —  Vesuvianite  f  yellow  garnet,  pargasite,  adularia, 
scapolite,  galenite,  blende,  chalcopyrite. 

PERU. — Crystallized  pyrite. 

PHIPPSBURG.  —  Yellow  garnet !  manganesian  garnet,  vesuvianite,  par- 
gasite,  axinite,  laumontite  !  chabazite,  an  ore  of  cerium  ? 

POLAND. — Vesuvianite,  smoky  quartz,  cinnamon  garnet. 

PORTLAND. — Prehnite,  actinolite,  garnet,  epidote,  amethyst,  calcite. 

POWNAL. — Black  tourmaline,  feldspar,  scapolite,  pyrite,  actinolite, 
apatite,  rose  quartz. 

RAYMOND. — Magnetite,  scapolite,  pyroxene,  lepidolite,  tremolite,  horn- 
blende, epidote,  orthoclase,  yellow  garnet,  pyrite,  vesuvianite. 

ROCKLAND. — Hematite,  tremolite,  quartz,  wad,  talc. 

RUMFORD. — Yellow  garnet,  vesuvianite,  pyroxene,  apatite,  scapolite. 

RUTLAND.  — Allanite. 

SANDY  RIVER. — Auriferous  sand. 

SANFORD,  York  Co.— Vesuvianite  f  albite,  calcite,  molybdenite,  epi- 
dote, black  tourmaline,  labradorite. 

SEARSMONT.  — Andalusite,  tourmaline. 

SOUTH  BERWICK.— Macle. 

STANDISH. — Columbite  ! 

STREAKED  MOUNTAIN. — Beryl!  black  tourmaline,  mica,  garnet. 

THOM ASTON. — Calcite,  tremolite,  Jiornblende,  sphene,  arsenical  iron 
(Owl's  Head),  black  manganese  (Dodge's  Mountain),  thomsonite,  talc, 
blende,  pyrite,  galenite. 

TOPSHAM.— Quartz,  galenite,  blende,  tungstite?  beryl,  apatite, 
molybdenite,  columbite. 

WALES. — ; Axinite  in  boulder,  alum,  copperas. 

WATERVILLE. — Crystallized  pyrite. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.          335 

WINDHAM  (near  the  bridge). — Staurolite,  spodumene,  garnet,  beryl, 
amethyst,  cyanite,  tourmaline. 
WINSLOW.  — Cassiterite. 

WINTHROP.- -Staurolite,  pyrite,  hornblende,  garnet,  copperas. 
WOODSTOCK. — Graphite,  hematite,  prehnite,  epidote,  calcite. 
YORK. — Beryl,  vivianite,  oxide  of  manganese. 


NEW  HAMPSHIRE. 

ACWORTH. — Beryl!!  mica!  tourmaline,  orthodase,  albite,  rose 
quartz,  columbitef  cyanite,  autunite. 

ALSTEAD. — Mica! !  albite ,  black  tourmaline,  molybdenite,  andalu- 
site,  Staurolite. 

AMHERST. —  Vesumanite,  yellow  garnet,  pargasite,  calcite,  amethyst. 

BARTLETT. — Magnetite,  hematite,  smoky  quartz. 

BATH.  —  Galenite,  chalcopyrite. 

BEDFORD. — Tremolite,  epidote,  graphite,  mica,  tourmaline,  alum, 
quartz. 

BELLOWS  FALLS. — Cyanite,  Staurolite,  wavellite. 

BRISTOL. — Graphite. 

CAMPTON.  — Beryl ! 

CANAAN. — Gold  in  pyrite,  garnet. 

CHARLESTON. — Staurolite  made,  andalusite  made,  bog-iron  ore, 
prehnite,  cyanite. 

CORNISH. — Stibnite,  tetrahedrite,  rutUein  quartz!  (rare),  Staurolite. 

CROYDEN. — lolite!  chalcopyrite,  pyrite,  pyrrhotite,  blende. 

ENFIELD. — Gold,  galenite.  Staurolite,  green  quartz. 

FRANCESTON. — Soapstonc,  arsenopyrite,  quartz  crystals. 

FRANCONIA. — Hornblende,  Staurolite !  epidote  !  zoisite,  hematite, 
magnetite,  black  and  red  manganesian  garnets,  arsenopyrite  (danaite), 
chalcopyrite,  molybdenite,  prehnite,  green  quartz,  malachite,  azurite. 

GILFORD  (Gunstock  Mt.) — Magnetic  iron  ore,  native  "lodestone." 

GILMANTOWN. — Tremolite,  epidote,  muscovite,  tourmaline,  limonite, 
red  and  yellow  quartz  crystals. 

GOSHEN. — Graphite,  black  tourmaline. 

GRAFTON. — Mica!  (extensively  quarried  at  Glass  Hill,  2  m.  S.  of 
Orange  Summit),  albite  !  blue,  green,  and  yellow  beryls  !  (i  m.  S.  of  O. 
Summit),  tourmaline,  garnets,  triphylite,  apatite,  fluorite. 

GRANTHAM. — Gray  Staurolite! 

GROTON. — Arsenopyrite,  blue  beryl,  muscovite  crystals. 

HANOVER. — Garnet,  black  tourmaline,  quartz,  cyanite,  labradoritet 
epidote,  anorthite. 

HAVERHILL. — Garnet!  arsenopyrite,  native  arsenic,  galenite,  blende, 
pyrite,  chalcopyrite,  magnetite,  marcasite,  steatite. 

HILLSBORO'  (Campbell's  Mountain). — Graphite. 

HINSDALE. — Rhodonite,  black  oxide  of  manganese,  molybdenite,  in- 
dicolite,  black  tourmaline. 

JACKSON. — Drusy  quartz,  tin  ore,  arsenopyrite,  native  arsenic,  fluo 
rite,  apatite,  magnetite,  molybdenite,  wolframite,  chalcopyrite. 

JAFFREY  (Monadnock  Mt.) — Cyanite,  limonite. 

KEENE. — Graphite,  soapstone,  milky  quartz,  rose  quartz. 

LANDAFF. — Molybdenite,  lead  and  iron  ores. 


336  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

LEBANON. — Bog-iron  ore,  arsenopyrite,  galenite,  magnetite,  pyrito. 

LISBON.  — Staurolite,  black  and  red  garnets,  magnetite,  hornblende, 
epidote,  zoisite,  hematite,  arsenopyrite,  galenite,  gold,  ankerite. 

LITTLETON. — Ankerite,  gold,  bornite,  chalcopyrite,  malachite,  me- 
naccanite,  chlorite. 

LYMAN. — Gold,  arsenopyrite,  ankerite,  dolomite,  galenite,  pyrite, 
copper,  pyrrhotite. 

LYME. — Cyanite  (N.  W.  part),  Hack  tourmaline,  rutile,  pyrite,  chal- 
copyrite  (E.  of  E.  village),  stibnite,  molybdenite,  cassiterite. 

MADISON. — Galenite,  blende,  chalcopyrite,  limonite. 

MERRIMACK. — Rutile!  (in  gneiss  nodules  in  granite  vein). 

MlDDLETO  WN.  — EutiU. 

MONADNOCK  MOUNTAIN. — Andalusite,  hornblende,  garnet,  graphite, 
tourmaline,  orthoclase. 

MOOSILAUKE  MT. — Tourmaline. 

MOULTONBOROUGH  (Red  Hill).—  Hornblende,  bog  ore,  pyrite,  tour- 
maline. 

NEWINGTON. — Garnet,  tourmaline. 

NEW  LONDON.— Beryl,  molybdenite,  muscovite  crystals. 

NEWPORT. — Molybdenite . 

ORANGE. — Blue  beryls!  Orange  Summit,  chrysoberyl,  mica(W.  side 
of  mountain),  apatite,  galenite,  limonite. 

ORFORD. — Brown  tourmaline  (now  obtained  with  difficulty),  steatite, 
rutile,  cyanite,  brown  iron  ore,  native  copper,  malachite,  galenite, 
garnet,  graphite,  molybdenite,  pyrrhotite,  melaconite,  chalcocite,  ripi- 
dolite. 

PELHAM. —Steatite. 

PIERMONT. — Micaceous  iron,  barite,  green,  white,  and  brown  mica, 
apatite,  titanic  iron. 

PLYMOUTH. — Columbite,  beryl. 

RICHMOND.—  lolite!  rutile,  steatite,  pyrite,  anthophyllite,  talc. 

RYE.  — Chiastolite. 

SADDLEBACK  MT. — Black  tourmaline,  garnet,  spinel. 

SHELBURNE. — Galenite,  black  blende,  chalcopyrite,  pyrite,  pyroluslte. 

SPRINGFIELD. — Beryls  (very  large,  eight  inches  diameter),  manga- 
nesian  garnets  !  black  tourmaline  !  in  mica  slate,  albite,  mica. 

SULLIVAN. — Tourmaline  (black)  in  quartz,  beryl. 

SURREY. — Amethyst,  calcite,  galenite,  limonite,  tourmaline. 

TAMWORTH  (near  White  Pond).  —Galenite. 

UNITY  (estate  of  James  Neal). — Copper  and  iron  pyrites,  chlorophyl- 
lite,  green  mica,  radiated  actinolite,  garnet,  titaniferous  iron  ore,  mag- 
netite, tourmaline. 

WALPOLE  (near  Bellows  Falls). — Made,  staurolite,  mica,  graphite. 

WAR  E. — Graphite. 

WARREN. — Chalcopyrite,  blende,  epidote,  quartz,  pyrite,  tremolite, 
galenite,  rutile,  talc,  molybdenite,  cinnamon  stone!  pyroxene,  horn- 
blende, beryl,  cyanite,  tourmaline  (massive)  vesuvianite. 

WATER VILLE.  — Labradorite,  chrysolite. 

WESTMORELAND  (south  part).—  Molybdenite!  apatite!  blue  feldspar, 
"bog  manganese  (north  village),  quartz,  fluorite,  chalcopyrite,  molybdite. 

WHITE  MTS.  (Notch  near  the  "Crawford  House"). — Green  octa- 
hedral fluorite,  quartz  crystals,  black  tourmaline,  chiastolite,  beryl, 
calcite,  amethyst,  amazon-stone. 


CATALOGUE   OF   AMERICAN  LOCALITIES   OP   MINERALS.          337 

WILMOT. — Beryl. 

WINCHESTER. — Pyrolusite,  rhodonite,  rhodochrosite,  psilomelane, 
magnetite,  granular  quartz,  spodumene. 


VERMONT. 

ADDTSON. — Iron  sand,  pyrite. 

ATHENS.— Steatite,  rhomb  spar,  actinolite,  garnet. 

BALTIMORE. — Serpentine,  pyrite  ! 

BELVIDERE.— Steatite,  chlorite. 

BENNINGTON. — Pyrolusite,  brown  iron  ore,  pipe  clay,  yellow  ochre. 

BERKSHIRE. — Epidote,  hematite,  magnetite. 

•  BETHEL.— Actinolite!  talc,  chlorite,  octahedral  iron,  rutile,  brown 
spar  in  steatite. 

BRANDON. — Braunite,    pyrolusite,    psilomelane,    limonite,    lignite, 
kaolinite,  statuary  marble  ;   graphite,  chalcopyrite. 

BRATTLEBOROUGH. — Black  tourmaline  in  quartz,  mica,  zoisite,  ru- 
tile, actinolite,  scapolite,  spodumene,  roofing  slate. 

BRIDGEWATER. — Talc,  dolomite,  magnetite,  steatite,  chlorite,  gold, 
native  copper,  blende,  galenite,  blue  spinel,  chalcopyrite. 

BRISTOL. — Rutile,  limonite,  manganese  ores,  magnetite. 

BROOKFIELD.  — Arsenopyrite,  pyrite. 

CABOT. — Garnet,  staurolite,  hornblende,  albite. 

CASTLETON. — Roofing  slate,  jasper,  manganese  ores,  chlorite. 

CAVENDISH.—  Garnet,  serpentine,  talc,  steatite,  tourmaline,  asbestus, 
tremolite. 

CHESTER. — Asbestus,  feldspar,  chlorite,  quartz. 

CHITTENDEN. — Psilomelane,  pyrolusite,  brown  iron  ore,  hematite 
and  magnetite,  galenite,  iolite. 

COLCHESTER.  —Brown  iron  ore,  iron  sand,  jasper,  alum. 

CORINTH. — Chalcopyrite  (has  been  mined),  pyrrhotite,  pyrite,  rutile. 

COVENTRY. — Rhodonite. 

CRAFTSBURY.— Mica  in  concentric  balls,  calcite,  rutile. 

DERBY.  ^-Mica  (adamsite). 

DUMMERSTON.  — Rutile,  roofing  slate. 

FAIR  HAVEN.—  Roofing  slate,  pyrite. 

FLETCHER.- — Pyrite,  magnetite,  acicular  tourmaline. 

GRAFTON. — The  steatite  quarry  referred  to  Graf  ton  is  properly  in 
Athens  ;  quartz,  actinolite. 

GUILFORD. — Scapolite,  rutile,  roofing  slate. 

HARTFORD. — Calcite,  pyrite/  cyanite,  quartz,  tourmaline. 

IRASBURGH. — Rhodonite,  psilomelane. 

JAY. — Ghromite,  serpentine,  amianthus,  dolomite. 

LOWELL. — Picrosmine,  amianthus,  serpentine,  talc,  chlorite. 

MARLBORO'. — Rhomb  spar,  steatite,  garnet,  magnetite,  chlorite. 

MIDDLEBURY.  — Zircon. 

MIDDLESEX.— Rutile !  (exhausted). 

MONKTOWN. — Pyrolusite,  brown  iron  ore,  pipe  clay,  feldspar. 

MORETOWN. — Smoky  quartz!  steatite,  talc,  wad,  rutile,  serpentine. 

MORRISTOWN. — Galenite. 

MOUNT  HOLLY. — Asbestus,  chlorite. 

NEW  FANE.— Glassy  and  asbestiform  actinolite,  steatite,  green  quarto 


338  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

(called  chrysoprase  at  the  locality),  chalcedony,  drusy  quartz,  garnet, 
chromic  and  titanic  iron,  rhomb  spar,  serpentine,  rutile. 

NORWICH. — Actinolite,  feldspar,  brown  spar>  in  talc,  cyanite,  zoisite, 
chalcopyrite,  pyrite. 

PITTSFORD. — Brown  iron  ore,  manganese  ores,  statuary  marble! 

PLYMOUTH. — Siderite,  magnetite  hematite,  gold,  galenite. 

PLYMPTON. — Massive  hornblende. 

PUTNEY. — Fluorite,  limonite,  rutile,  and  zoisite,  in  boulders,-  stau- 
rolite. 

READING. — Glassy  actinolite  in  talc. 

READSBORO'. — Glassy  actinolite,  steatite,  hematite. 

RIPTON. — Brown  iron  ore,  augite  in  boulders,  octahedral  pyrite. 

ROCHESTER. — Rutile,  hematite  eryst.,  magnetite  in  chlorite  slate. 

ROCKINGHAM  (Bellows  Falls). — Cyanite,  indicolite,  feldspar,  tour- 
maline, fluorite,  calcite,  prehnite,  staurolite. 

ROXBURY. — Dolomite,  talc,  serpentine,  asbestus,  quartz. 

RUTLAND. — Magnesite,  white  marble,  hematite,  serpentine,  pipe  clay. 

SALISBURY. — Brown  iron  ore. 

SHARON. — Quartz  crystals,  cyanite. 

SHOREHAM. — Pyrite,  black  marble,  calcite. 

SHREWSBURY. — Magnetite  and  chalcopyrite. 

STIRLING. — Chalcopyrite,  talc,  serpentine. 

STOCKBRIDGE.  — Arsenopy rite,  magnetite. 

STRAFFORD. — Magnetite  and  chalcopyrite  (has  been  worked),  native 
copper,  hornblende,  copperas. 

THETFORD. — Blende,  galenite,  cyanite.  chrysolite  in  basalt,  pyrrho- 
tite,  feldspar,  roojing  slate,  steatite,  garnet. 

TOWNSHEND. — Actinolite,  black  mica,  talc,  steatite,  feldspar. 

TROY. — Magnetite,  talc,  serpentine,  picrosmine,  amianthus,  steatite, 
one  mile  southeast  of  village  of  South  Troy,  on  the  farm  of  Mr.  Pierce, 
east  side  of  Missisco,  chromite,  zaratite. 

VERSHIRE. — Pyrite,  chalcopyrite,  tourmaline,  arsenopyrite,  quartz. 

WARDSBORO'. — Zoisite,  tourmaline,  tremolite,  hematite. 

WARREN. — Actinolite,  magnetite,  wad,  serpentine. 

WATERBURY. — Arsenopyrite,  chalcopyrite,  rutile,  quartz,  serpen- 
tine. 

WATERVILLE. — Steatite,  actinolite,  talc. 

WEATHERSFIELD. — Steatite,  hematite,  pyrite,  tremolite. 

WELLS'  RIVER. — Graphite. 

WESTFIELD. — Steatite,  chromite,  serpentine. 

WESTMINSTER. — Zoisite  in  boulders. 

WINDHAM. — Glassy  actinolite,  steatite,  garnet,  serpentine. 

WOODBURY. — Massive  pyrite. 

WOODSTOCK. — Quartz  crystals,  garnet,  zoisite. 

MASSACHUSETTS. 

ALFORD. — Galenite,  pyrite. 

ATHOL. — Allanite,  fibrolite  (?),  epidote  !  babingtonite  ? 

AUBURN. — Masonite. 

JSKTXKE,.— Rutile  !  mica,  pyrite,  beryl,  feldspar,  garnet. 

GREAT  BARRINGTON. — Tremolite. 

BEDFORD. — Garnet. 


CATALOGUE  OP  AMERICAN  LOCALITIES  OP  MINERALS.          339 

BELCHERTON.  —All  anite. 

BERNARDSTON. — Magnetite. 

BEVERLY. — Columbite,  green  feldspar,  cassiterite. 

BLANFORD. — Serpentine,  anthophyllite,  actinolite  !  chromite,  cyanite. 
rose  quartz  in  boulders. 

BOLTON.—  Scapolite  f  petalite,  sphene,  pyroxene,  nuttalite,  diopside, 
boltonite,  apatite,  magnesite,  rhomb  spar,  allanite,  yttrocerite  !  spinel. 

BOXBOROUGH. — Scapolite,  spinel,  garnet,  augite,  actinolite,  apatite. 

BRIGHTON.  — Asbestus. 

BRIMFIELD  (road  leading  to  Warren). — lolite,  adularia,  molybdenite, 
mica,  garnet. 

CARLISLE. — Tourmaline,  garnet!  scapolite,  actinolite. 

CHARLESTOWN. — Prehnite,  laumontite,  stilbite,  chabazite,  quartz 
crystals,  melanolite. 

CHELMSFORD. — Scapolite  (chelmsfordite),  chondrodite,  Hue  spinel, 
amianthus!  rose  quartz. 

CHESTER. — Hornblende,  scapolite,  zoisite,  spondumene,  indicolite, 
apatite,  magnetite,  chromite,  stilbite,  heulandite,  analcite  and  cha- 
bazite. At  the  Emery  Mine,  Chester  Factories. — Corundum,  marga- 
rite,  diaspore,  epidote,  corundophilite,  chloritoid,  tourmaline,  menac- 
canite  !  rutile,  biotite,  indianite  ?  andesite  ?  cyanito,  amesite. 

CHESTERFIELD. — Blue,  green,  and  red  tourmaline,  cleavelandite 
(albite),  lepidolite,  smoky  quartz,  microlite,  spodumene,  cyanite,  apatite, 
rose  beryl,  garnet,  quartz  crystals,  staurolite,  cassiterite,  tolumbite, 
zoisite,  uranite,  brookite  (eumanite),  scheelite,  anthophyllite,  bornite. 

CON  WAY. — Pyrolusite,  fluorite,  zoisite,  rutile!!  native  alum,  gale- 
nite. 

CUMMINGTON.—  Rhodonite!  cummingtonite  (hornblende),  marcasite, 
garnet. 

DEERFIELD. — Chabazite,  heulandite,  stilbite,  amethyst,  carnelian, 
chalcedony,  agate. 

FITCHBURG  (Pearl  Hill).—  Beryl,  staurolite!  garnets,  molybdenite. 

FOXBOROL  GH.  —Pyrite,  anthracite. 

FRANKLIN.  — Amethyst. 

GOSHEN. — Mica,  alfoite,  spondumene!  blue  and  green  tourmaline, 
beryl,  zoisite,  smoky  quartz,  columbite,  tin  ore,  galenite,  beryl  (go- 
shenite),  cymatolite. 

GREENFIELD  (in  sandstone  quarry,  half  mile  east  of  village). — Allo- 
phane,  white  and  greenish. 

HATFIELD. — Barite,  galenite,  blende,  chalcopyrite. 

HAWLEY. — Micaceous  iron,  massive  pyrite,  magnetite,  zoisite. 

HEATH. — Pyrite,  zoisite. 

HINSDALE. — Brown  iron  ore,  apatite,  zoisite. 

HUBBARDSTON. — Massive  pyrite. 

HUNTINGTON  (name  changed  from  Norwich). — Apatite!  Hack  tour* 
maline,  beryl,  spodumene !  triphylite  (altered),  blende,  quartz  crystals, 
cassiterite. 

LANCASTER.— Cyanite,  chiastolite!  apatite,  staurolite,  pinite,  and* 
lusite. 

LEE. — Tremolite!  sphene!  (east  part). 

LEVERETT. — Barite,  galenite,  blende,  chalcopyrite. 

LEYDEN. — Zoisite,  rutile. 

LTTTLEFIELD. — Spinel,  scapolite,  apatite, 


340  SUPPLEMENT   TO   DESCRIPTIONS   OF  SPECIES. 

LYNNFIELD. — Magnesite  on  serpentine. 

M  ENDON.  — Mica  !  chlorite. 

MIDDLEFIELD.  —  Glassy  actinolite,  rhomb  spar,  steatite,  serpentine, 
feldspar,  drusy  quartz,  apatite,  zoisite,  nacrite,  chalcedony,  talc! 
deweylite. 

MILBURY. — Vermiculite. 

NEW  BRAINTREE. — Black  tourmaline. 

NEWBURY. — Serpentine,  chrysotile,  epidote,  massive  garnet,  side- 
rite. 

NEWBURYPORT.—  Serpentine,  nemalite,  uranite. — Argentiferous  ga 
lenite,  tetrahedrite,  chalcopyrite,  pyrargyrite,  etc. 

NORTHFIELD. — Columbite,  fibrolite,  cyanite. 

NORWICH.— See  HUNTINGTON. 

PALMER  (Three  Rivers).—  Feldspar,  calcite. 

PELHAM. — Asbestus,  serpentine,  quartz  crystals,  beryl,  molybdenite, 
green  hornstone,  epidote,  amethyst,  corundum,  vermiculite  (pelhamite). 

PLAINFIELD. — (Jummingtonite,  pyrolusite,  rhodonite. 

RICHMOND. — Brown  iron  ore,  gibbsite  !  allophane. 

ROCKPORT. — Danalite,  cryophyllite,  annite,  cyrtolite  (altered  zircon), 
green  and  white  orthoclase,  fergusonite. 

ROWE. — Epidote,  talc. 

SOUTH  ROYALSTON.— y&ery?  /  /  (now  obtained  with  great  difficulty), 
mica! !  feldspar  !  allanite.  Four  miles  beyond  old  loc.,  on  farm  oi 
Solomon  Heywood,  mica  !  beryl !  feldspar  !  menaccanite. 

RUSSEL. — Schiller  spar  (diallage  ?),  mica,  serpentine,  beryl,  galenite, 
chalcopyrite. 

SALEM. — In  a  boulder,  cancrinite,  sodalite,  elaeolite. 

SHEFFIELD.  —Asbestus,  pyrite,  native  alum,  pyrolusite,  rutile. 

SHELBURNE.  — Rutile. 

SHUTESBURY  (east  of  Locke's  Pond). — Molybdenite. 

SOUTHAMPTON. — Galenite,  cerussite,  anglesite,  wulfenite,  fluorite, 
barite,  pyrite,  chalcopyrite,  blende,  phosgenite,  pyromorphite,  stolzite, 
chrysocolla. 

STERLING. — Spodumene,  chiastolite,  siderite,  arsenopyrite,  blende, 
galenite,  chalcopyrite,  pyrite,  sterlingite  (damourite). 

STONEH  AM.  — Nephrite. 

STURBRIDGE. — Graphite,  garnet,  apatite,  bog  ore. 

SWAMPSCOT. — Orthite,  feldspar. 

TAUNTON  (one  mile  south). — Paracolumbite  (titanic  iron). 

TURNER'S  FALLS  (Conn.  River). — Chalcopyrite,  prehnite,  chlorite, 
siderite,  malachite. 

TYRINGHAM. — Pyroxene,  scapolite. 

UXBRIDGE.  — Galenite. 

WARWICK. — Massive  garnet,  radiated  black  tourmaline,  magnetite, 
beryl,  epidote. 

WASHINGTON. — Graphite. 

WESTFIELD. — Schiller  spar  (diallage),  serpentine,  steatite,  cyanite, 
scapolite,  actinolite. 

WESTFORD. — Andalusite  ! 

WEST  HAMPTON. — Galenite,  argentine,  pseudomorphous  quartz. 

WEST  SPRINGFIELD. — Prehnite,  ankerite,  satin  spar,  celestite. 

WEST  STOCKBRIDGE. — Limonite,  fibrous  pyrolusite,  siderite. 

WHATELY. — Native  copper,  galenite. 


CATALOGUE   OP   AMERICAN  LOCALITIES   OF  MINERALS.          341 

WILLIAMSBURG. — Zoisite,  pseudomorphous  quartz,  apatite,  rose  and 
smoky  quartz,  galenite,  pyrolusite,  chalcopyrite. 

WILLIAMSTOWN.—  Cryst.   quartz. 

WINDSOR. — Zoisite,  actinolite,  rutile! 

WORCESTER.  — Arsenopy rite,  idocrase,  pyroxene,  garnet,  amianthus, 
bucholzite,  siderite,  galenite. 

WORTHIN  GTON. — Cyanite. 

ZOAR.—  Bitter  spar,  talc. 

RHODE  ISLAND. 

BRISTOL.  — A  methyst. 

COVENTRY. — Mica,  tourmaline. 

CRANSTON. — Actinolite  in  talc,  graphite,  cyanite,  mica,  melanterite. 

CUMBERLAND. — Manganese,  epidote,  actinolite,  garnet,  titaniferous 
Iron,  magnetite,  red  hematite,  chalcopyrite,  bornite,  malachite,  azu- 
rite,  calcite,  apatite,  feldspar,  zoisite,  mica,  quartz  crystals,  ilvaite. 

DIAMOND  HILL.  -  Quartz  crystals,  hematite. 

FOSTER. — Cyanite,  hematite. 

GLOUCESTER. — Magnetite  in  chlorite  slate,  feldspar. 

JOHNSTON. — Talc,  brown  spar,  calcite,  garnet,  epidote,  pyrite,  he- 
matite, magnetite,  chalcopyrite,  malachite,  azurite. 

NATIC.— See  WARWICK. 

NEWPORT. — Serpentine,  quartz  crystals. 

PORTSMOUTH. — Anthracite,  graphite,  asbestus,  pyrite,  chalcopyrite. 

SMITHFIELD. — Dolomite,  calcite,  bitter  spar,  siderite,  nacrite,  serpen- 
tine (bowenite),  tremolite,  asbestus,  quartz,  magnetic  iron  in  chlorite 
slate,  talc  !  octahedrite,  feldspar,  beryl. 

VALLEY  FALLS.— Graphite,  pyrite,  hematite. 

WARWICK  (Natic  village). — Masonite,  garnet,  graphite. 

W  ESTERLY.  — Menaccanite. 

WOONSOCKET.  — Cyanite. 


CONNECTICUT 


»  BERLIN. — Barite,  datolite,  blende,  quartz  crystals. 
BOLTON. — Staurolite,  chalcopyrite. 
BRADLEYVILLE  (Litchfield). — Laumontite. 
BRISTOL. — Chalcocite,  chalcopyrite,  barite,  bornite,  dllophane,  pyro- 
orphite,  calcite,  malachite,  galenite,  quartz. 
BROOKFIELD.— Galenite,  calamine,  blende,  spodumene,  pyrrhotite. 
CANAAN. — Tremolite  and  white  augite  !  in  dolomite,  canaanite  (mas- 
sive pyroxene). 

CHATHAM. — Arsenopyrite,  smaltite,  cloanthite  (chathamite),  scoro 
dite,  niccolite,  beryl,  erythrite. 

CHESHIRE.—  Barite!  chalcocite,  bornite,  malachite,  kaolin,  natrolite, 
prehnite,  chabazite,  datolite. 
CHESTER. — Sillimanitef  zircon,  epidote. 
CORNWALL.— Graphite,  pyroxene,  actinolite,  sphene,  scapolite. 
DANBURY.  — Danburite,    oligoclase,   moonstone,   brown  tourmaline, 
orthoclase,  pyroxene,  parathorite. 

FARMINGTON.— Prehnite,  chabazite,  agate,  native  copper ;  in  trap, 
diabantite. 


342  SUPPLEMENT    TO    DESCRIPTIONS    OP    SPECIES. 

GRANBY. — Green  malachite. 

GREENWICH.— Slack  tourmaline. 

HADDAM. — Chrysoberyl!  beryl!  epidote!  tourmaline!  feldspar,  gar- 
net! iolite!  oligoclase,  chlorophyllite  !  automolite,  magnetite^  adularia, 
apatite,  columbite!  (hermannolite),  zircon  (calyptolitc),  mica,  pyrite, 
marcasite,  molybdenite,^  allanite,  bismuth  ochre,  bismutite. 

HADLYME. — Chabazite  and  stilbite  in  gneiss  with  epidote  and  gar- 
net. 

HARTFORD. — Datolite  (Rocky  Hill  quarry). 

KENT.—  Limonite,  pyrolusite. 

LITCHFIELD. — Cyanite  with  corundum,  apatite,  and  andalusite,  me- 
naccanite  (washingtonite),  chalcopyrite,  diaspore,  niccoliferous  pyrrho- 
tite,  margarodite. 

LYME. — Garnet,  sunstone. 

MIDDLEFIELD  FALLS. — Datolite,  chlorite,  etc.,  in  amygdaloid. 

MIDDLETOWN. — Mica,  lepidolite  with  green  and  red  tourmaline, 
albite,  feldspar,  columbite !  prehnite,  garnet  (sometimes  octahedral), 
beryl,  topaz,  uranite,  apatite,  pitchblende  ;  at  lead  mine,  galenite,  chal- 
copyrite, blende,  quartz,  calcite,  fluorite,  pyrite  sometimes  capillary. 

MILFORD. — Sahlite,  pyroxene,  asbestus,  zoisitc,  verd-antique,  marble, 
pyrite. 

NEW  BRITAIN. — Agate,  diabantile,  barite,  datolite,  prehnite,  calcite, 
dolomite. 

NEW  HAVEN.— Serpentine,  sahlite,  stilbite,  prehnite,  chabazite, 
laumontite,  gmelinite,  apophyllite,  topazolite. 

NEWTOWN. — Cyanite,  diaspore,  rutile,  damourite,  cinnabar. 

NORWICH.  — Sillimanite,  monazite  !  iolite,  corundum,  feldspar. 

OXFORD  (near  Humphreysville). — Cyanite,  chalcopyrite. 

PORTLAND. — Orthoclase,  albite,  muacovite,  biotite,  beryl,  tourmaline, 
columbite,  apatite. 

PLYMOUTH.  —Galenite,  heulandite,  fluorite,  chlorypliyllite  !  garnet. 

REDDING  (near  the  line  of  Danbury). — Pyroxene,  garnet.  Near 
Branchville  R.  R.  depot :  Albite,  microcline,  hebronite,  spodumene ! 
cymatolite,  damourite,  eosphorite.  triploidite,  reddingite,  dickinsonite, 
lithiophilite,  rhodocltrosite,  fairlieldite,  apatite,  microlite,  columuife, 
garnet,  pyrite,  tourmaline,  staurolite,  uranmite,  torbernite,  autunite, 
vivianite,  triphylite. 

ROARING  BROOK  (Cheshire).—  Datolite  f  calcite,  prehnite,  saponite. 

ROXBURY.  —Siderite,  blende,  pyrite  !  !  galenite,  quartz,  chalcopyrite, 
arsenopyrite,  limonite. 

SALISBURY. — Limonite,  pyrolusite,  triplite,  turgite. 

SAYBROOK.—  Molybdenite,  stilbite,  plumbago. 

SEYMOUR. — Native  bismuth,  arsenopyrite,  pyrite. 

SIMSBURY. — Copper  glance,  green  malachite. 

SOUTHBURY.  — Rose  quartz,  laumontite,  prehnite,  calcite,  barite. 

SOUTHINGTON. — Barite,  datolite,  asteriated  quartz  crystals.  • 

STAFFORD. — Massive  pyrites,  alum,  copperas. 

STONINGTON. — Stilbite  and  chabazite  on  gneiss. 

TARIFF  VILLE.  — Datolite. 

TOLLAND.— Staurolite,  massive  pyrites. 

TRUMBULL  and  MONROE. — Chlorophane,  topaz,  beryl,  diaspore,  pyr- 
Jrhotite,  pyrite,  niccolite,  scheelite,  wolframite  (pseudomorph  of  scheel- 
ite),  rutile,  native  bismuth,  tungstic  acid,  siderite,  arsenopyrite. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.  343 

argentiferous  galenite,  blende,  scapolite,  tourmaline,  garnet,  albitc, 
augite,  graphic  tellurium  {?),  margarodite. 

WASHINGTON. — Tripolite,  menaccanite!  (washingtonite  of  Shepard), 
rhodochrosite,  natrolite.  andalusite  (New  Preston),  cyanite. 

WATERTOWN,  near  the  Naugatuck. — White  sahlite,  monazite. 

WEST  FARMS. — Asbestus. 

WILLIMANTIC. — Topaz,  monazite,  ripidolite. 

WINCHESTER  and  WILTON. — Asbestus,  garnet. 


NEW  YORK. 

ALBANY  CO.— BETHLEHEM.— Calcite,  stalactite,  stalagmite,  calca- 
reous sinter,  snowy  gypsum. 

COEYMAN'S  LANDING. —Gypsum,  epsoni  salt,  quartz  crystals  at 
Crystal  Hill,  three  miles  south  of  Albany. 

GUILDERLAND. — Petroleum,  anthracite,  and  calcite,  on  the  banks 
of  Norman's  Kill,  two  miles  south  of  Albany. 

WATER VLIET. — Quartz  crystals,  yellow  drusy  quartz. 

ALLEGHANY  CO.— CUBA.— Calcareous  tufa,  petroleum,  3£  miles 
from  the  village. 

CATTARAUGUS  CO.— FREEDOM.—  Petroleum. 

CAYUGA  CO.— AUBURN.— Celestite,  calcite,  nuor  spar,  epsomite. 

SPRINGPORT. — At  Thompson's  plaster  beds,  sulphur!  selenite. 

SPRING VILLE. — Nitrogen  springs. 

UNION  SPRINGS. — Selenite,  gypsum. 

CHATAUQUE  CO.— FREDONIA. — Petroleum,  carburetted  hydrogen. 

LAON  A.  — Petroleum. 

CLINTON  CO.  —ARNOLD  IRON  TATSK.— Magnetite,  epidote,  molybde- 
nite. 

FINCH  ORE  BED.— Calcite,  green  and  purple  fluor. 

COLUMBIA  CO.—  AUSTERLITZ.  -  -Earthy  manganese,  wnlfenite, 
chalcocite  ;  Livingston  lead  mine,  galenite. 

CHATHAM. — Quartz,  pyrite  in  cubic  crystals  in  slate  (Hillsdale). 

CANAAN. — Chalcocite,  chalcopyrite. 

HUDSON.— Epidote,  selenite! 

NEW  LEBANON. — Nitrogen  springs,  graphite,  anthracite  ;  at  the 
Ancram  lead  mine,  galenite,  barite,  blende,  wulfenite  (rare),  chalcopy- 
rite, calcareous  tufa;  near  the  city  of  Hudson,  epsom  salt,  brown 
spar,  wad. 

DUTCHESS  CO.— AMENIA.— Dolomite,  limonite,  turgite. 

BEEKM  AN.  — Dolomite. 

DOVER. — Dolomite,  tremolite,  garnet  (Foss  ore  bed),  staurolite, 
limonite. 

FISHKILL. — Dolomite  ;  near  Peck vi lie,  talc,  asbestus,  graphite,  horn- 
Uende,  augite,  actinolite,  hydrous  anthophyllite,  limonite. 

NORTH  EAST. — Chalcocite,  chalcopyrite,  galenite,  blende. 

RHINEBECK.— Calcite,  green  feldspar,  epidote,  tourmaline. 

UNION  VALE. — At  the  Clove  mine,  gibbsite,  limonite. 

ESSEX  CO.— ALEXANDRIA.— Kirby's  graphite  mine,  graphite,  py- 
roxene, scapolite,  sphene. 

CROWN  POINT. — Apatite  (eupyrchroite  of  Emmons),  brown  tourma- 
line !  in  the  apatite,  chlorite,  quartz  crystals,  pink  and  blue  calcite, 


344  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

pyrite ;  a  short  distance  south  of  J.  C.  Hammond's  house,  garnet, 
scapolite,  chalcopyrite,  aventurine  feldspar,  zircon,  magnetic  iron 
(Peru),  epidote,  mica. 

KEENE. — Scapolite. 

LE>VIS. — labular  spar,  colophonite,  garnet,  labradorite,  hornblende, 
actinolite  ;  ten  miles  south  of  the  village  of  Keeseville,  arsenopyrite. 

LONG  POND. — Apatite,  garnet,  pyroxene,  idocrase,  coccolite!  I  scapo- 
lite, magnetite,  Hue  calcite. 

MclNTYRE. — Labradorite,  garnet,  magnetite. 

MORIAH,  at  Sandford  Ore  Bed. — Magnetite,  apatite,  allanite  !  lan- 
thanite,  actinolite,  and  feldspar ;  at  Fisher  Ore  Bed,  magnetite,  feld- 
spar, quartz  ;  at  Hail  Ore  Bed,  or  "  New  Ore  Bed,"  magnetite,  zircons; 
on  Mill  brook,  calcite,  pyroxene,  hornblende,  albite  ;  in  the  town  of 
Moriah,  magnetite,  black  mica  ;  Barton  Hill  Ore  Bed,  albite. 

NEWCOMB. — Labradorite,  feldspar,  magnetite,  hypersthene. 

PORT  HENRY. — Brown  tourmaline,  mica,  rose  quartz,  serpentine, 
green  and  black  pyroxene,  hornblende,  cryst.  pyrite,  graphite,  wollas- 
tonite,  pyrrhotite,  adularia ;  phlogopite!  at  Cheever  Ore  Bed,  with 
magnetite  and  serpentine. 

ROGER'S  ROCK. — Graphite,  wollastonite,  garnet,  collophonite,  feld- 
spar, adularia,  pyroxene,  sphene,  coccolite. 

SCHROON. — Calcite,,  pyroxene,  chondrodite. 

TicoNDEROGA. — Graphite !  pyroxene,  sahlite,  sphene,  black  tour- 
maline, cacoxene  ?  (Mt.  Defiance). 

WESTPORT. — Labradorite,  prehnite,  magnetite. 

WILLSBORO'. —  Wollastonite,  colophonite,  garnet,  green  coccolite,  horn- 
blende. 

ERIE  CO.— ELLICOTT'S  MILLS. — Calcareous  tufas. 
.    FRANKLIN   CO.—  CHATEAUGAY.  —  Nitrogen   springs,   calcareous 
tufas. 

M ALONE. — Massive  pyrite,  magnetite. 

GENESEE  CO.— Acid  springs  containing  sulphuric  acid. 

GREENE  CO.— CATSKILL.— (Mctte. 

DIAMOND  HILL. — Quartz  crystals. 

HAMILTON  CO.— LONG  LAKE.— Blue  calcite. 

HERKIMER  CO.—  FAIRFIELD.— Quartz  crystals,  fetid  barite. 

LITTLE  FALLS. — Quartz  crystals  I  barite,  calcite,  anthracite,  pearl 
spar,  smoky  quartz;  one  mile  south  of  Little  Falls,  calcite,  brown 
spar,  feldspar. 

MIDDLEVILLE.  — Quartz  crystals  !  calcite,  brown  and  pearl  spar,  an- 
thracite. 

NEWPORT. — Quartz  crystals. 

SALISBURY. — Quartz  crystals!  blende,  galenite,  pyrite,  chalcopyrite. 

STARK. — Fibrous  celestite,  gypsum. 

JEFFERSON  CO.— ADAMS.— Fluor,  calc  tufa,  barite. 

ALEXANDRIA. — On  the  S.  E.  bank  of  Muscolonge  Lake,  fluorite 
(exhausted),  phlogopite,  chalcopyrite,  apatite  ;  on  High  Island,  in  the  St. 
Lawrence  River,  feldspar,  tourmaline,  hornblende,  orthoclase,  celestite. 

ANTWERP.— Sterling  iron  mine,  hematite,  chalcodite,  siderite,  mil- 
lerite,  red  hematite,  crystallized  quartz,  yellow  aragonite,  niccoliferous 
pyrite,  quartz  crystals,  pyrite ;  at  Oxbow,  calcite !  porous  coralloidal 
heavy  spar  ;  near  Viooman's  lake,  calcite !  vesuvianite,  phlogopite  ! 
pyroxene,  sphene,  fluorite,  pyrite,  chalcopyrite  ;  also  feldspar,  bog-iron 


CATALOGUE    OF    AMERICAN   LOCALITIES    OP   MINERALS.  345 

ore,  scapolite  (farm  of  Eggleson),  serpentine,  tourmaline  (yellow, 
rare). 

BROWNSVILLE. — Celestite  in  slender  crystals,  calcite  (four  miles 
from  Watertown). 

NATURAL  BRIDGE. — Oieseckite!  steatite  pseudomorphous  after  py- 
roxene, apatite. 

NEW  CONNECTICUT. — Sphene,  brown  phlogopite. 

OMAR. — Beryl,  feldspar,  hematite. 

PHILADELPHIA. — Garnets  on  Indian  River,  in  the  village. 

PAMELIA. — Agaric  mineral,  calc  tufa. 

PIERREPONT. — Tourmaline,  sphene,  scapolite,  hornblende. 

PILLAR  POINT.—  Massive  barite  (exhausted). 

THERESA. — Fluorite,  calcite,  hematite,  hornblende,  quartz  crystal, 
serpentine  (associated  with  hematite),  celestite,  strontianite. 

WATERTOWN.— Tremolite,  agaric  mineral,  calc  tufa,  celestite. 

WILNA. — One  mile  north  of  Natural  Bridge,  calcite. 

LEWIS  CO. — DIANA  (localities  mostly  near  junction  of  crystalline 
and  sedimentary  rocks,  and  within  two  miles  of  Natural  Bridge). — 
Scapolite  !  wollastonite,  green  coccolite,  feldspar,  tremolite,  pyroxene ! 
sphene!  !  mica,  quartz  crystals,  drusy  quartz,  cryst.  pyrite,  pyrrhotite, 
blue  calcite,  serpentine,  rensselaerite,  zircon,  graphite,  chlorite,  hema- 
tite, bog-iron  ore,  iron  sand,  apatite. 

GREIG. — Magnetite,  pyrite. 

LOWVILLE. — Calcite,  fluorite,  pyrite,  galenite,  blende,  calc  tufa. 

MARTINSBURGH. — Wad,  galenite,  etc.,  but  mine  not  now  opened, 
calcite. 

MONROE  CO. — ROCHESTER. — Pearl  spar,  calcite,  snowy  gypsum, 
fluor,  celestite,  galenite,  blende,  barite,  hornstone. 

MONTGOMERY  CO.—  PALATINE.—  Quartz  crystals,  drusy  quartz, 
anthracite,  hornstone,  agate,  garnet. 

ROOT. — Drusy  quartz,  blende,  barite,  stalactite,  stalagmite,  galenite, 
pyrite. 

NEW  YORK  CO.— CORLEAR'S  HOOK.— Apatite,  brown  and  yellow 
feldspar,  sphene. 

HARLEM. — Epidote,  apophyllite,  stilbite,  tourmaline,  vivianite, 
lamellar  feldspar,  mica. 

KINGSBRIDGE. — T)'emolite,pyroxene,  mica,  tourmaline,  pyrite,  rutile, 
dolomite. 

NEW  YORK. — Serpentine,  amianthus,  actinolite,  pyroxene,  hydrous 
anthophyllite,  garnet,  staurolite,  molybdenite,  graphite,  chlorite, 
jasper,  necronite,  feldspar.  In  the  excavations  for  the  4th  Avenue 
tunnel,  1875,  harmotome,  stilbite,  chabazite,  heulandite,  etc. 

NIAGARA  CO. — LEWISTON.  — Epsomite. 

LOCKPORT. — Celestite,  calcite,  selenite,  anhydrite,  fluorite,  dolomite, 
blende. 

NIAGARA  FALLS. — Calcite,  fluorite,  blende,  dolomite. 

ONEIDA  CO.— BOONVILLE.— Calcite,  wollastonite,  coccolite. 

CLINTON. — Blende,  lenticular  argillaceous  iron  ore  in  rocks  of  the 
Clinton  group,  strontianite,  celestite,  the  former  covering  the  latter. 

ONONDAGA  CO.—  CAMILLUS.—  Selenite  and  fibrous  gypsum. 

COLD  SPRING.— Axinite. 

MANLIUS. — Gypsum  and  fluor. 

SYRACUSE.— Serpentine,  celestite,  selenite,  barite. 


SUPPLEMENT   TO   DESCRIPTIONS   OP   SPECIES. 

ORANGE  CO.— CORNWALL.—  Zircon,  chondrodite,  hornblende,  spinel, 
massive  feldspar,  fibrous  epidote,  hudsonite,  menaccanite,  serpentine, 
coccolite. 

DEER  PARK. — Cryst.  pyrite,  galenite. 

MONROE. — Mica  !  sphene  !  garnet,  colophonite,  epidote,  chondrodite, 
aUanite,  bucholzite,  brown  spar,  spinel,  hornblende,  talc,  menaccanite, 
pyrrhotite,  pyrite,  chromite,  graphite,  rastolyte.  moronolite. 

At  WILKS  and  O'NEILL  Mine  in  Monroe. — Aragonite,  magnetite, 
dimagnetite  (pseud.?),  jenkinsite,  asbestus,  serpentine,  mica,  hortono- 
lite. 

At  Two  PONDS  in  Monroe. — Pyroxene!  chondrodite,  hornblende, 
scapolite!  zircon,  sphene,  apatite. 

At  GREENWOOD  FURNACE  in  Monroe. — Chondrodite,  pyroxene! 
mica,  hornblende,  spinel,  scapolite,  biotite!  menaccanite. 

At  FOREST  OF  DEAN. — Pyroxene,  spinel,  zircon,  scapolite,  horn- 
blende. 

TOWN  OP  WARWICK,  WARWICK  VILLAGE. — Spinel!  zircon,  serpen- 
tine! brown  spar,  pyroxene!  hornblende!  pseudomorphous  steatite, 
feldspar!  (Rock  Hill),  menaccanite,  clintonite,  tourmaline  (R.  H.), 
rutile,  sphene,  molybdenite,  arsenopyrite,  marcasite,  pyrite,  yellow 
iron  sinter,  quartz,  jasper,  mica,  coccolite. 

AMITY. — Spinel!  garnet,  scapolite,  hornblende,  vesuvianite,  epidote! 
clintonite !  magnetite,  tourmaline,  warwickite,  apatite,  chondrodite, 
talc!  pyroxene!  rutile,  menaccanite,  zircon,  corundum,  feldspar, 
sphene,  calcite,  serpentine,  schiller  spar  (?),  silvery  mica. 

EDENVILLE. — Apatite,  chondrodite  !  hair -brown  hornblende  !  tremo- 
lite,  spinel,  tourmaline,  warwickite,  pyroxene,  sphene,  mica,  feldspar, 
arsenopyrite,  orpiment,  rutile,  menaccanite,  scorodite,  chalcopyrita, 
leucopyrite  (or  lollingite),  allanite. 

WEST  POINT. — Feldspar,  mica,  scapolite,  sphene,  hornblende,  allanite. 

PUTNAM  CO.— BREWSTER,  Tilly  Foster  Iron  Mine.— Chondrodite! 
(also  humite  and  clino-humite)  crystals  very  rare,  magnetite,  dolomite, 
serpentine,  pseudomorphs,  brucite,  enstatite,  ripidolite,  biotite,  actino- 
lite,  apatite,  pyrrhotite,  fluorite,  albite,  epidote,  sphene. 

ANTHONY'S  NOSE,  at  top,  pyrite,  pyrrhotite,  pyroxene,  hornblende, 
magnetite. 

CARMEL  (Brown's  quarry). — Anthophyllite,  schiller  spar  (?),  orpi- 
ment, arsenopyrite,  epidote. 

COLD  SPRING. — Chabazite,  mica,  sphene,  epidote. 

PATTERSON. — White  pyroxene!  calcite,  asbestus,  tremolite,  dolomite, 
massive  pyrite. 

PHILLIPSTOWN. — Tremolite,  amianthus,  serpentine,  sphene,  diopside, 

C'.n  coccolite,  hornblende,  scapolite,  stilbite,  mica,  laumontite,  gur- 
te,  calcite,  magnetite,  chromite. 

PHILLIPS  Ore  Bed. — Hyalite,  actinolite,  massive  pyrite. 
RENSSELAER  CO.— Hoosic.— Nitrogen  springs. 
LANSINGBURGH. — Epsomite,  quartz  crystals,  pyrite. 
TROY. — Quartz  crystals,  pyrite,  selenite. 
RICHMOND  CO.— ROSSVILLE. —Lignite,  cryst.  pyrite. 
QUARANTINE. — Asbestus,  amianthus,  aragonite,  dolomite,  gurhofite 
brucite,  serpentine,  talc,  magnesite. 
ROCKLAND  CO.— CALDWELL.— Calcite. 
GRASSY  POINT.— Serpentine,  actinolite. 


CATALOGUE   OP   AMERICAN   LOCALITIES   OF   MINERALS.          347 

HAVEB  STRAW. — Hornblende,  barite. 

LADENTOWN.  — Zircon,  malachite,  cuprite. 

PIERMONT. — Datolite,  stilbite,  apophyllite,  stellite,  prehnite,  tliom- 
sonite,  calcite,  chabazite. 

ST.  LAWRENCE  CO.—  CANTON.—  Massive  pyrite,  calcite,  brown 
tourmaline,  sphene,  serpentine,  talc,  rensselaerite ,  pyroxene,  hematite, 
chalcopyrite. 

DE  KALE.—  Hornblende,  barite,  fluorite,  trcmolite,  tourmaline,  blende, 
graphite,  pyroxene,  quartz  (spongy),  serpentine. 

EDWARDS, — Brown  and  silvery  mica  !  scapolite,  apatite,  quartz  crys- 
tals, actinolite,  tremolite!  hematite,  serpentine,  magnetite. 

FINE. — Black  mica,  hornblende. 

FOWLER. — Barite,  quartz  crystals  !  hematite,  blende,  galenite,  tremo- 
lite, chalcedony,  bog  ore,  satin  spar  (assoc.  with  serpentine),  pyrite, 
chalcopyrite,  actinolite,  rensselaerite  (near  Somerville). 

GOUVERNEUR. — Calcite !  serpentine!  Jwrriblende!  scapolite!  ortho- 
clase,  tourmaline  !  idocrase  (one  mile  south  of  G.),  pyroxene,  malaco- 
lite,  apatite,  rensselaerite,  serpentine,  sphene,  fluorite,  barite  (farm  of 
Judge  Dodge \  black  mica,  phlogopite,  tremolite!  asbestus,  hematite, 
graphite,  vesuvianite  (near  Somerville  in  serpentine),  spinel,  houghite, 
scapolite,  phlogopite,  dolomite  ;  three-quarters  of  a  mile  west  of  Som- 
erville, chondrodite,  spinel  ;  two  miles  north  of  Somerville,  apatite, 
pyrite,  brown  tourmaline  /  ! 

HAMMOND. — Apatite!  zircon!  (farm  of  Mr.  Hardy),  orthoclase  (loxo 
case\  pargasite,  barite.  pyrite,  purple  fluorite,  dolomite. 

HERMON. — Quartz  crystals,  hematite,  siderite,  pargasite,  pyroxene, 
serpentine,  tourmaline,  bog-iron  ore. 

MACOMB. — Blende,  mica,  galenite  (on  land  of  James  Averill), 
ephene. 

MINERAL  POINT,  Morristown. — Fluorite,  blende,  galenite,  phlogo- 
pite  (Pope's  Mills),  barite. 

OGDENSBURGH. — Labradorite . 

PITCAIRN.— Satin  spar,  associated  with  serpentine. 

POTSDAM. — Hornblende! ;  eight  miles  from  Potsdam,  on  road  to 
Pierrepont,  feldspar,  tourmaline,  black  mica,  hornblende. 

ROSSIE  (Iron  Mines). — Barite,  hematite,  coralloidal  aragonite  in 
mines  near  Somerville,  limonite,  quartz  (sometimes  stalactitic  at 
Parish  Iron  Mine\  pyrite,  pearl  spar. 

ROSSIE  Lead  Mine. — Calcite!  galenite!  pyrite,  celestite,  chalcopyrite, 
hematite,  cerussite,  anglesite,  octahedral  fluor,  black  phlogopite. 

Elsewhere  in  ROSSIE. — Calcite,  barite,  quartz  crystals,  chondrodite 
(near  Yellow  Lake),  feldspar!  pargasite!  apatite,  pyroxene,  horn- 
blende, sphene,  zircon,  mica,  fluorite,  serpentine,  automolite,  pearl 
spar,  graphite. 

RUSSEL. — Pargasite,  specular  iron,  quartz  (dodec.),  calcite,  serpen- 
tine, rensselaerite,  magnetite. 

SARATOGA  CO.— GREENFIELD.— Chrysoberyl!  garnet!  tourma- 
line !  'mica,  feldspar,  apatite,  graphite,  aragonite  (in  iron  mines). 

SCHOHARIE  CO.— BALL'S  CAVE,  and  others.— Calcite,  stalactites. 

CARLISLE. — Fibrous  barite,  cryst.  and  jibrous  calcite. 

MIDDLEBURY. — Asphaltic  coal,  calcite. 

SHARON. — Calcareous  tufa. 

SCHOHARIE. — Fibrous  celestite,  strontianite !  cryst.  pyrite! 


348  SUPPLEMENT    TO    DESCRIPTIONS    OF    SPECIES. 

SENECA  CO.—  CANOGA.— Nitrogen  springs. 

SULLIVAN  CO.— WURTZBORO'.— Galenite,  Uende,  pyrite,  chalco> 
pyrite. 

TOMPKINS  CO.— ITHACA. -Calcareous  tufa. 

ULSTER  CO.  —  ELLENVILLE.  —  Galenite,  blende,  chalcopyrite  / 
quartz,  brookite. 

M  ARBLETOWN.  — Pyrite. 

WARREN  CO. — CALDWELL. — Massive  feldspar. 

CHESTER. — Pyrite,  tourmaline,  rutile,  chalcopyrite. 

DIAMOND  ISLE  (Lake  George). — Calcite,  quartz  crystals. 

GLENN'S  FALLS. — Rhomb  spar. 

JOHNSBUHGH. — Fluorite!  zircon!  graphite,  serpentine,  pyrite. 

WASHINGTON  CO.— FORT  ANN.— Graphite,  serpentine. 

GRANVILLE. — Lamellar  pyroxene,  massive  feldspar,  epidote. 

WAYNE  CO.— WOLCOTT.— Barite. 

WESTCHESTER  CO.— ANTHONY'S  NOSE.—  Apatite,  pyrite,  calcite! 
in  very  large  tabular  crystals,  grouped,  and  sometimes  incrusted  with 
drusy  quartz. 

DAVENPORT'S  NECK. — Serpentine,  garnet,  sphene. 

EASTCHESTER. — Blende,  pyrite,  chalcopyrite,  dolomite. 

HASTINGS. — Tremolite,  white  pyroxene. 

NEW  ROCHELLE. — Serpentine,  brucite,  quartz,  mica,  tremolite,  gar- 
net, magnesite. 

:   PEEKSKILL. — Mica,  feldspar,  hornblende,  stilbite,   sphene ;  three 
miles  south,  emery. 

RYE. — Serpentine,  chlorite,  black  tourmaline,  tremolite. 

SING  SING. — Pyroxene,  tremolite,  pyrite,  beryl,  azurite,  green  mala- 
chite, cerussite,  pyromorphite,  anglesite,  vauquelinite,  galenite,  native 
silver,  chalcopyrite. 

WEST  FARMS. — Apatite,  tremolite,  garnet,  stilbite,  heulandite,  cha- 
bazite,  epidote,  sphene. 

YONKEUS. — Tremolite,  apatite,  calcite,  analcite,  pyrite,  tourmaline. 

YORKTOWN. — Fibrolite,  monazite,  magnetite. 

WYOMING  CO.— WYOMING.— Rock  salt. 


NEW  JERSEY. 

ANDOVER  IRON  MINE  (Sussex  Co.)— Will emite,  brown  garnet. 

ALLENTOWN  (Monmouth  Co.) — Vivianite,  dufrenite. 

BELLVILLE. — Copper  mines. 

.  BERGEN.— Calcite!  datolite!  pectolite  !  analcite,  apophyllite!  gme~ 
Unite,  prehnite,  sphene,  stilbite,  natrolite,  heulandite,  laumontite,  cha- 
bazite,  pyrite,  pseudomorphous  steatite  imitative  of  apophyllite, 
diabantite. 

BRUNSWICK. — Copper  mines :    native  copper,   malachite,  mountain 
leather. 

BRYAM. — Chondrodite,  spinel,  at  Roseville,  epidote. 

CANTWELL'S  BRIDGE  (Newcastle  Co.),  three  miles  west. — Vivian- 
ite. 

DANVILLE  (Jemmy  Jump  Ridge). — Graphite,  chondrodite,  augite, 
mica. 

FLEMINGTON, — Copper  mines. 


CATALOGUE   OF  AMERICAN   LOCALITIES   OF   MINERALS.  349 

FRANKFORT. — Serpentine. 

FRANKLIN  and  STERLING  (Sussex  Co.). — Spinel !  garnet  i  rhodonite  ! 
willemite  !  franklinite  !  zincite  !  dysluite  !  hornblende,  tremolitK,  chon- 
drodite,  white  scapolitc,  black  tourmaline,  epidote,  mi^a,  actinohte, 
augite,  sahlite,  cocblite.  asbestus,  jcffcrsontte  (augite).  calamine,  graph- 
ite, fluorite,  beryl,  galenite,  serpentine,  honey-colored  sphene,  quart/, 
chalcedony,  amethyst,  zircon,  molybdenite,  vivianite,  tephroite,  rhodo- 
chrosite,  aragonite,  sussexite,  chalcophanite,  rcepperite,  calcozincito, 
vanuxemite,  gahnite,  hetaerolitc.  Also  algerite  in  gran,  limestone. 

FRANKLIN  and  WARWICK  MTS. — Pyrite. 

GREENBROOK. — Copper  mines. 

GRIGGSTOWN. — Copper  mines. 

HAMBURGH. — One  mile  north,  spinel !  tourmaline,  phlogopite,  horn- 
blende, limonite,  hematite. 

HOBOKEN.  — Serpentine  (marmolite),  brucite,  nemalite  (or  fibrous  bru- 
cite),  aragonite,  dolomite. 

HURDSTOWN. — Apatite,  pyrrhotite,  magnetite. 

IMLAYSTOWN. — Vivianite. 

LOCKWOOD. — Graphite,  chondrodite,  talc,  augite,  quartz,  green  spi- 
nel. 

MONTVILLE  (Morris  Co.) — Serpentine,  chrysotile. 

MULLICA  HILL  (Gloucester  Co.) — Vivianite  lining  belemnites  and 
other  fossils. 

I    NEWTON. — Spinel,  blue,  pink,  and  white  corundum,  mica,  vesuvian- 
ite,  hornblende,  tourmaline,  scapolite,  rutile,  pyrite,  talc,  calcite,  barite, 
pseudomorphous  steatite. 
PATERSON.  — Datolite. 
VERNON. — Serpentine,  spinel,  hydrotalcite. 


PENNSYLVANIA.* 


ADAMS  CO.— GETTYSBURG. — Epidote,  fibrous  and  massive. 

BERKS  Co. — MORGANTOWN. — At  Jones's  mines,  one  mile  east  of 
Morgantown,  malachite,  native  copper,  cJirysocolla,  magnetite,  allo- 
phane,  pyrite,  chalcopyrite,  aragonite,  apatite,  talc,  venerite  ;  two 
miles  N.  E.  from  Jones's  mine,  graphite,  sphene  ;  at  Steele's  mine, 
one  mile  N.  W.  from  St.  Mary's,  Chester  Co.,  magnetite,  micaceous 
iron,  coccolite,  brown  garnet. 

READING. — Smoky  quartz  crystals,  zircon,  stilbite,  iron  ore ;  near 
Pricetown,  zircon,  allanite,  epidote  ;  at  Eckhardt's  Furnace,  allanite 
with  zircon  ;  at  Zion's  Church,  molybdenite  ;  near  Kutztown,  in  the 
Crystal  Cave,  stalactites  ;  at  Fritz  Island,  apophyllite,  thomsonite,  cha- 
bazite,  calcite,  azurite,  malachite,  magnetite,  chalcopyrite,  stibnite, 
prochlorite,  precious  serpentine. 

BUCKS  CO.— BUCKINGHAM  TOWNSHIP. — Crystallized  quartz  ;  near 
New  Hope,  vesuvianite,  epidote,  barite. 

SOUTHAMPTON. — Near  the  village  of  Feasterville,  in  the  quarry  of 
George  Van  Arsdale,  graphite,  pyroxene,  sahlite,  coccolite,  sphene, 
green  mica,  calcite,  wollastonite,  glassy  feldspar  sometimes  opalescent, 
phlogopite,  blue  quartz,  garnet,  zircon,  pyrite,  moroxite,  scapolite. 

*  See  also  the  Report  on  the  Mineralogy  of  Pennsylvania,  by  Dr.  F.  A.  Genth, 
1875, 


850  SUPPLEMENT  TO   DESCRIPTIONS  OF   SPECIES. 

NEW  BRITAIN. — Dolomite,  galenite,  blende,  malachite. 

CARBON  CO.  — SUMMIT  HILL,  in  coal  mines. — Kaolinite. 

CHESTER  CO. — AVONDALE.— Asbestus,  tremolite,  garnet,  opal. 

BIRMINGHAM  TOWNSHIP.  —  Amethyst,  smoky  quartz,  serpentine, 
beryl ;  in  Ab'm  Darlington's  lime  quarry,  calcite. 

EAST  BRADFORD. — Near  Buffington's  bridge,  on  the  Brandy  wine, 
green,  blue,  and  gray  cyanite,  the  gray  cyanite  found  loose  in  the 
soil,  in  crystals  ;  on  the  farms  of  Dr.  Elwyn,  Mrs.  Foulke,  Wm.  Gib- 
bons, and  Saml.  Entrikin,  amethyst.  At  Strode's  mill,  asbestus,  mag- 
nesite,  anthophyllite,  epidote,  aquacrepitite,  oligoclase,  drusy  quartz, 
collyrite  ?  on  O.-;borne's  Hill,  wad,  manganesian  garnet  (massive),  sphene 
schorl  ;  at  Caleb  Cope's  lime  quarry,  fetid  dolomite,  necronite,  garnets, 
blue  cyanite,  yellow  actinolite  in  talc  ;  near  the  Black  Horse  Inn,  indu- 
rated talc,  rutile ;  on  Amos  Davis's  farm,  orthite!  massive,  from  a  grain 
to  lumps  of  one  pound  weight ;  near  the  paper-mill  on  the  Brandy- 
wine,  zircon,  associated  with  titaniferous  iron  in  blue  quartz. 

WEST  BRADFORD. — Near  the  village  of  Marshalton,  green  cyanite, 
rutile,  scapolite,  pyrite,  staurolite  ;  at  the  Chester  County  Poor-house 
limestone  quarry,  chesterlite  !  in  crystals  implanted  on  dolomite,  ru- 
tile !  in  brilliant  acicular  crystals,  which  are  finely  terminated,  calcite 
in  scalenohedrons,  zoisite,  damourite  ?  in  radiated  groups  of  crystals 
on  dolomite,  quartz  crystals ;  on  Smith  &  McMullin's  farm,  epidote. 

CHARLESTOWN. — Pyromorphite,  cerussite,  galenite,  quartz. 

COVENTRY. — Allanite,  near  Pughtown. 

SOUTH  COVENTRY. — In  Chrisman's  limestone  quarry,  near  Coventry 
village,  augite,  sphene,  graphite,  zircon  in  iron  ore  (about  half  a  mile 
from  the  village). 

EAST  FALLOWFIELD. — Soapstone. 

EAST  QOSHEN. — Serpentine,  asbestus,  magnetite  (lodestone),  gar- 
net. 

ELK. — Menaccanite  with  muscovite,  chromite  ;  at  Lewisville,  black 
tourmaline. 

WEST  QOSHEN. — On  the  Barrens,  one  mile  north  of  West  Chester, 
amianthus,  serpentine,  cellular  quartz,  jasper,  chalcedony,  drusy 
quartz,  chlorite,  marmolite,  indurated  talc,  magnesite  in  radiated  crys- 
tals on  serpentine,  hematite,  asbestus;  near  R.  Taylor's  mill,  chromite 
in  octahedral  crystals,  deweylite,  radiated  magnesite,  aragonite,  stauro- 
lite, garnet,  asbestus,  epidote  ;  zoisite  on  hornblende  at  West  Chester 
water- works  (not  accessible  at  present). 

NEW  GARDEN. — At  Nivin's  limestone  quarry,  broicn  tourmaline,  ne- 
cronite, scapolite,  apatite,  brown  and  green  mica,  rutile,  aragonite, 
fibrolite,  kaolinite,  tremolite. 

KENNETT. — Actinolite,  brown  tourmaline,  brown  mica,  epidote,  tre- 
molite, scapolite,  aragonite  ;  on  Wm.  Cloud's  farm,  sunstone!  !  cha- 
bazite,  sphene.  At  Pearce's  old  mill,  zoisite,  epidote,  sunstone  ;  sun- 
stone  occurs  in  good  specimens  at  various  places  in  the  range  of  horn- 
blende rocks  running  through  this  township  fromN.  E.  toS.  W. 

LOWER  OXFORD.— Garnets,  pyrite  in  cubic  crystals. 

LONDON  GROVE. — Rutile,  jasper,  chalcedony  (botryoidal),  large  and 
rough  quartz  crystals,  epidote  ;  on  Wm.  Jackson's  farm,  ydlow  and 
Hack  tourmaline,  tremolite,  rutile,  green  mica,  apatite  ;  at  Pusey's 
quarry,  rutile,  tremolite. 

EAST  MARLBOROUGH. — On  the  farm  of  Bailey  &  Brother,  one  mile 


CATALOGUE   OP   AMERICAN  LOCALITIES   OP  MINERALS.          351 

south  of  Unionville,  bright  yellow  and  nearly  white  tourmaline,  ches- 
terlite,  albite,  pyrite  ;  near  Marlborough  meeting-house,  epidote,  ser- 
pentine, acicular  black  tourmaline  in  white  quartz  ;  zircon  in  small 
perfect  crystals  loose  in  the  soil  at  Pusey's  sawmill,  two  miles  S.  W. 
of  Unionville. 

WEST  MARLBORO  UGH. — Near  Logan's  quarry,  staurolite,  cyanite, 
yellow  tourmaline,  rutile,  garnets  ;  near  Doe  Run  village,  hematite, 
scapolite,  tremolite  ;  in  R.  Baily's  limestone  quarry,  two  and  a  half 
miles  S.  VV.  of  Unionville,  fibrous  tremolite,  cyanite,  scapolite. 

NEWLIN. — On  the  serpentine  barrens,  one  and  a  half  mile  N.  E.  of 
Unionville,  corundum  !  massive  and  crystallized,  also  in  crystals  in 
albite,  often  in  loose  crystals  covered  with  a  thin  coating  of  steatite, 
spinel  (black),  talc,  picrolite,  brucite,  green  tourmaline,  with  flat  pyram- 
idal terminations  in  albite,  unionite,  (rare),  enphyllit?,  mica  in  hexagonal 
crystals,  feldspar,  beryl!  in  hexagonal  crystals  one  of  which  weighs 
51  Ibs.,  pyrite  in  cubic  crystals,  chromic  iron,  drusy  quartz,  green 
quartz,  actinolite,  emerylits,  chloritoid,  diallage,  oliyoclase ;  on  John- 
son Patterson's  farm,  massive  corundum,  titaniferous  iron,  clinocMore, 
emerylite,  sometimes  colored  green  by  chrome,  albite,  orthoclase,  hal- 
loysite,  margarite,  garnets,  beryl;  on  J.  Lesley's  farm,  corundum, 
crystallized  and  in  massive  lumps  one  of  which  weighed  5,200  Ibs., 
diaspore ! !  emerylite!  euphyllite,  crystallized!  green  tourmaline,  in 
transparent  crystals  in  the  euphyllite,  orthoclase  ;  two  miles  N.  of 
Unionville,  magnetite  in  octahedral  crystals ;  one  mile  E.  of  Union- 
ville, hematite;  in  Edwards's  old  limestone  quarry,  purple  fluorite, 
rutile. 

EAST  NOTTINGHAM.— Asbestus,  chromite  in  crystals,  hallite,  beryl. 

WEST  NOTTINGHAM. — At  Scott's  chrome  mine,  chromite,  foliated 
talc,  marmolite,  serpentine,  chalcedony,  rhodochrome  ;  near  Moro  Phil- 
lips's  chrome  mine,  asbestus ;  at  the  magnesia  quarry,  deweylite,  mar- 
molite, magnesite,  leelite,  serpentine,  chromite  ;  near  Fremont  P.  O., 
corundum. 

WEST  PIKELAND. — In  the  iron  mines  near  Chester  Springs,  gibbsite, 
zircon,  turgite,  hematite  (stalactitical  and  in  geodes),  gothite. 

PENN. — Garnets,  agalmatolite. 

PENNSBURY. — On  John  Craig's  farm,  brown  garnets,  mica ;  on  J. 
Dil worth's  farm,  near  Fairville,  muscovite !  in  the  village  of  Fair- 
ville, sunstone ;  near  Brinton's  Ford,  on  the  Brandywine,  chondrodite, 
yphene,  diopside,  augite,  cocoolite ;  at  Mendenhall's  old  limestone 
quarry,  fetid  quartz,  sunstone  ;  at  Swain's  quarry,  orthoclase. 

POCOPSON. — On  the  farms  of  John  Entrikin  and  Jos.  B.  Darlington, 
amethyst. 

SADSBURY. — Rutile  !  f  splendid  geniculated  crystals  are  found  loose 
in  the  soil  for  seven  miles  along  the  valley,  and  particularly  near  the 
village  of  Parkesburg,  where  they  sometimes  occur  weighing  on» 
pound,  doubly  geniculated  and  of  a  deep  red  color ;  near  Sadsbury 
village,  amethyst,  tourmaline,  epidote,  milk  quartz. 

SCHUYLKILL. — In  the  railroad  tunnel  at  PHCENIXVILLE,  dolomite! 
sometimes  coated  with  pyrite,  quartz  crystals,  yellow  blende,  brookite, 
calcite  in  hexagonal  crystals  enclosing  pyrite;  at  the  WHEATLEY, 
BROOKDALE,  and  CHESTER  COUNTY  LEAD  MINES,  one  and  a  half 
mile  S.  of  Phrenixville,  pyromorphite  !  cerussite  !  galenite,  anglesite  f  ! 
quartz  crystals,  chalcopyrite,  barite,  fluorite  (white),  stolzite,  wulfenite  } 


352  SUPPLEMENT   TO   DESCRIPTIONS   OP    SPECIES. 

calamine,  vanadinite,  blende !  mimetite  /  descloizite,  gothite,  chryso- 
colla,  native  copper,  malachite,  azurite,  limonite,  calcite,  sulphur,  py- 
rite,  melaconite,  pseudomalachite,  gersdorffite,  chalcocite  ?  covellite. 

THORNBURY. — On  Jos.  H.  Brinton's  farm,  muscovite  containing  ajcic- 
ular  crystals  of  tourmaline,  rutile,  titaniferous  iron. 

TREDYFFRIN. — Pyrite  in  cubic  crystals  loose  in  the  soil. 

UWCHLAN. — Massive  bine  quartz,  graphite. 

WARREN. — Melanite,  feldspar. 

WEST  GOSHEN  (one  mile  from  West  Chester). — Chromite. 

WILLISTOWN. — Magnetite,  chromite,  actinolite,  asbestus. 

WEST  TOWN. — On  the  serpentine  rocks,  3  miles'  S.  of  West  Ches- 
ter, dinochlore  !  jefferisite  !  mica,  asbestus,  actinolite,  magnesite,  talc, 
titaniferous  iron,  magnetite  and  massive  tourmaline. 

EAST  WHITELAND. — Pyrite,  in  cubic  crystals,  quartz  crystals. 

WEST  WHITELAND. — At  Gen.  Trimble's  iron  mine  (southeast),  stal- 
actitic  hematite  !  wavellite  I  !  in  radiated  stalactites,  gibbsite,  coeruleo- 
lactile. 

WARWICK. — At  the  Elizabeth  mine  and  Keim's  old  iron  mine 
adjoining,  one  mile  N.  of  Knauertown,  aplome  garnet !  in  brilliant 
dodecahedrons,  flosferri,  pyroxene,  micaceous  hematite,  pyrite  in  bright 
octahedral  crystals  in  calcite,  chrysocolla,  chalcopyrite  massive  and  in 
single  tetrahedral  crystals,  magnetite,  fuscicular  hornblende  !  bornite, 
malachite,  brown  garnet,  calcite,  byssolite  !  serpentine  ;  near  the  village 
of  St.  Mary's,  magnetite  in  dodecahedral  crystals,  melanite,  garnet ', 
actinolite  in  small  radiated  nodules  ;  at  the  Hopewell  iron  mine,  one 
mile  IS.  W.  of  St.  Mary's,  magnetite  in  octahedral  crystals. 

COLUMBIA  CO. — At  Webb's  mine,  yellow  blende  in  calcite  ;  near 
Bloomburg,  cryst.  magnetite. 

DAUPHIN  CO. — NEAR  HUMMELSTOWN.  —Green  garnets,  cryst. 
amoky  quartz,  feldspar,  micaceous  hematite,  stilbite,  chrysocolla. 

DELAWARE  CO. — ASTON  TOWNSHIP. — Amethyst,  corundum,  eme- 
rylite,  staurolite,  fibrolite,  black  tourmaline,  margarite,  sunstone,  asbes- 
tus, anthophyllite,  steatite  ;  near  Tyson'o  mill,  garnet,  staurolite ;  at 
Peter's  milldam  in  the  creek,  pyrope  garnet. 

BIRMINGHAM. — Fibrolite,  kaolin  (abundant),  crystals  of  rutile,  ame- 
thyst ;  at  Bullock's  old  quarry,  zircon,  bucholzite,  nacrite,  yellow  crys- 
tallized quartz,  feldspar. 

BLUE  HILL. — Green  quartz  crystals,  spinel. 

CHESTER. — Amethyst,  black  tourmaline,  beryl,  crystals  of  feldspar, 
garnet,  cryst.  pyrite,  molybdenite,  molybdite,  chalcopyrite,  kaolin,  ura- 
ninite,  muscovite,  orthoclase,  bismutite. 

CHICHESTER. — Near  Trainer's  milldam,  beryl,  tourmaline,  crystals 
of  feldspar,  kaolin  ;  on  Wm.  Eyre's  farm,  tourmaline. 

CONCORD. — Mica,  feldspar,  kaolin,  drusy  quartz,  meerschaum,  stel- 
lated tremolite,  anthophyllite,  fibrolite,  acicular  crystals  of  rutile,  py- 
rope in  quartz,  amethyst,  actinolite,  manganesian  garnet,  beryl ;  in 
Green's  creek,  pyrope  garnet. 

DARBY. — Blue  and  gray  cyanite,  garnet,  staurolite,  zoisite,  quartz, 
beryl,  chlorite,  mica,  limonite. 

EDGEMONT. — Amethyst,  oxide  of  manganese,  crystals  of  feldspar; 
one  mile  east  of  Edgemont  Hall,  rutile  in  quartz. 

GREEN'S  CREEK. — Garnet  (so-called  pyrope). 
-  HAVERFORD. — Staurolite  with  garnet. 


CATALOGUE    OF   AMERICAN   LOCALITIES    OF   MINERALS.  353 

MARPLE. — Tourmaline,  andalusite,  amethyst,  actinolite,  antJiophyl* 
lite,  talc,  radiated  actinolite  in  talc,  chromite,  drusy  quartz,  beryl, 
cryst.  pyrite,  menaccanite  in  quartz,  chlorite. 

MIDDLETOWN. — Amethyst,  beryl,  black  mica,  mica  with  reticulated 
magnetite  between  the  plates,  manganesian  garnets!  large  trapezo 
hedral  crystals,  some  3  in.  in  diameter,  indurated  talc,  hexagonal 
crystals  of  rutile,  crystals  of  mica,  green  quartz !  anthophyllite,  radi- 
ated tourmaline,  staurolite,  titanic  iron,  fibrolite,  serpentine  ;  at  Len- 
ni,  chlorite,  green  and  bronze  vermiculite!  green  feldspar ;  at  Mineral 
Hill,  fine  crystals  of  corundum,  one  of  which  weighs  If  lb.,  actinolite 
in  great  variety,  bronzite,  green  feldspar,  moonstone,  sunstone,  graphic 
granite,  magnesite,  octahedral  crystals  of  chromite  in  great  quantity, 
beryl,  chalcedony,  asbestus,  fibrous  hornblende,  rutile,  staurolite,  ine- 
lanosiderite,  hallite  ;  at  Painter's  Farm,  near  Dismal  Run,  zircon  with 
oligoclase,  tremolite,  tourmaline  ;  at,  the  Black  Horse,  near  Media, 
corundum ;  at  Hibbard's  Farm  and  at  Fairlamb's  Hill,  chromite  in. 
brilliant  octahedrons. 

NEWTOWN. — Serpentine,  hematite,  enstatite,  tremolite. 

UPPER  PROVIDENCE. — Anthophyllite,  tremolite,  radiated  asbestus, 
radiated  actinolite,  tourmaline,  beryl,  green  feldspar,  amethyst  (one 
found  on  Morgan  Hunter's  farm  weighing  over  7  Ibs.),  andalusite! 
(one  terminated  crystal  found  on  the  farm  of  Jas.  Worrell  weighs  7£ 
Ibs. ) ;  at  Blue  Hill,  very  fine  crystals  of  blue  quartz  in  chlorite,  amian- 
thus in  serpentine,  zircon. 

LOWER  PROVIDENCE. — Amethyst,  green  mica,  garnet,  large  crystals 
of  feldspar  !  (some  over  100  Ibs.  in  weight). 

RADNOR. — Garnet,  marmolite,  deweylite,  chromite,  asbestus,  mag- 
nesite, talc,  blue  quartz,  picrolite,  limonite,  magnetite. 

SPRINGFIELD. — Andalusite,  tourmaline,  beryl,  titanic  iron,  garnet ; 
on  Fell's  Laurel  Hill,  beryl,  garnet ;  near  Beattie's  mill,  staurolite, 
apatite  ;  near  Lewis's  paper-mill,  tourmaline,  mica. 

THORNBURY. — Amethyst. 

HUNTINGDON  CO.— NEAR  FRANKSTOWN.— In  the  bed  of  a  stream 
and  on  the  side  of  a  hill,  fibrous  celestite  (abundant),  quartz  crystals. 

LANCASTER  CO.— DRUMORE  TOWNSHIP.— Quartz  crystals. 

FULTON. — At  Wood's  chrome  mine,  near  the  village  of  Texas,  bru- 
citelf  zaratite  (emerald  nickel),  pennite!  ripidolite!  Mmmererite! 
baltimorite,  chromite,  williamsite,  chrysolite!  marmolite,  picrolite^ 
hydromagnesite,  dolomite,  magnesite,  aragonite,  calcite,  serpentine, 
hematite,  menaccanite,  genthite,  chrome-garnet,  bronzite,  millerite  ; 
at  Low's  mine,  hydromagnesite,  brucite  (lancasterite),  picrolite,  magne- 
site, williamsite,  chromic  iron,  talc,  zaratite,  balumorite,  serpentine, 
hematite  ;  on  M.  Boice's  farm,  one  mile  N.  W.  of  the  village,  pyrite  in 
cubes  and  various  modifications,  anthophyllite;  near  Rock  Springs, 
chalcedony,  carnelian,  moss  agate,  green  tourmaline  in  talc,  titanic  iron, 
chromite,  octahedral  magnetite  in  chlorite;  at  Reynolds's  old  mine, 
calcite,  talc,  picrolite,  chromite  ;  at  Carter's  chrome  mine,  brookitc. 

GAP  MINES. — Chalcopyrite,  pyrrhotite  (niccoliferous),  millerite  in 
botryoidal  radiations,  mvianite  I  (rare),  actinolite,  siderite,  hisingerite, 
pyrite. 

PEQUA  VALLEY.— Eight  miles  south  of  Lancaster,  argentiferous 
galenite  (said  to  contain  250  to  300  ounces  of  silver  to  the  ton?),  vau- 
.quelinite,  rutile  at  Pequea  mine ;  four  miles  N.  W.  of  Lancaster,,  on 


354  SUPPLEMENT  TO   DESCRIPTIONS   OP   SPECIES. 

the  Lancaster  and  Harrisburg  Railroad,  calamite,  galenite,  blende; 
pyrite  in  cubic  crystals  is  found  iu  great  abundance  near  the  city  of 
Lancaster  ;  at  the  Lancaster  zinc  mines,  calamine,  blende,  tennantite  ? 
smithsonite  (pseud,  of  dolomite),  aurichalcite. 

LEBANON  CO.  —  CORNWALL.  —  Magnetite,  pyrite  (cobaltif erous\ 
chalcopyrite,  native  copper,  azurite,  malachite,  chrysocolla,  cuprite  (hy- 
drocuprite),  allophane,  brochantite,  serpentine,  quartz  pseudomorphs  ; 
galenite  (with  octahedral  cleavage),  fluorite,  covellite,  hematite  (mica- 
ceous), opal,  asbestus. 

LEHIGH  CO. — FRIEDENSVILLE. — At  the  zinc  mines,  calamine, 
smithsonite,  hydrozincite,  massive  blende,  greenockite,  quartz,  allo- 
phane, zinciferous  clay,  mountain  leather,  aragonite,  sauconite  ;  near 
Allentown,  magnetite,  pipe-iron  ore  ;  near  Bethlehem,  on  S.  Mountain, 
allanite,  with  zircon  and  altered  sphene  in  a  single  isolated  mass  of 
syenite,  magnetite,  martite,  black  spinel,  tourmaline,  chalcocite. 

MIFFLIN  CO.— Strontianite. 

MONROE  CO. — In  CHERRY  VALLEY. — Calcite,  chalcedony,  quartz; 
in  Poconac  Valley,  near  Judge  Mervine's,  cryst.  quartz. 

MONTGOMERY  CO. — CONSHOHOCKEN. — Fibrous  tourmaline,  me- 
naccanite,  aventurine  quartz,  phyllite  ;  in  the  quarry  of  Geo.  Bullock, 
calcite  in  hexagonal  prisms,  aragonite. 

LOWER  PROVIDENCE. — At  the  Perkiomen  lead  and  copper  mines, 
near  the  village  of  Shannonville,  azurite,  blende,  galenite,  pyromor- 
phite,  cerussite,  wulfenite,  anglesite,  barite,  calamine,  chalcopyrite, 
malachite,  chrysocolla,  brown  spar,  cuprite,  covellite  (rare),  melaco- 
nite.  libethenite,  pseudomalachite. 

WHITE  MARSH. — At  D.  O.  Hitner's  iron  mine,  five  and  a  half  miles 
from  Spring  Mills,  limonite  in  geodes  and  stalactites,  gothite,  pyro- 
lusite,  wad,  lepidocrocite  ;  at  Edge  Hill  Street,  North  Pennsylvania 
Railroad,  titanic  iron,  braunite,  pyrolusite  ;  one  mile  S.  W.  of  Hitner's 
iron  mine,  limonite,  velvety,  stalactitic,  and  fibrous,  fibres  three  inches 
long,  turgite,  gothite,  pyrolusite,  velvet  manganese,  wad  ;  near  Marble 
Hall,  at  Hitner's  marble  quarry,  white  marble,  granular  barite,  resem- 
bling marble  ;  at  Spring  Mills,  limonite,  pyrolusite,  gflthite  ;  at  Flat 
Rock  Tunnel,  opposite  Manayunk,  stilbite,  lieulandite,  chabasite,  ilvaite, 
beryl,  feldspar,  mica. 

LAFAYETTE,  at  the  Soapstone  quarries. — Talc,  jefferisite,  garnet, 
albite,  serpentine,  zoisite,  staurolite,  chalcopyrite  ;  at  Rose's  Serpen- 
tine quarry,  opposite  Lafayette,  enstatite,  serpentine. 

NORTHAMPTON  CO.— BUSHKILL  TOWNSHIP.— Crystal  Spring  on 
Blue  Mountain,  quartz  crystals. 

Near  E ASTON. — Zircon!  (exhausted),  nephrite,  coccolite,  tremolite, 
pyroxene,  sahlite,  limonite,  magnetite,  purple  calcite. 

WILLIAMS   TOWNSHIP.  —  Pyrolusite  in  geodes  in  limonite  beds, 


go'thite  (lepidocrocite)  at  Glendon. 
NORTHUMBERLj 


.AND  CO.— Opposite  SELIN'S  GROVE. —Cala- 
mine. 

PHILADELPHIA  CO.— FRANKPORD.— Titanite  in  gneiss,  apophyl- 
lite  ;  on  the  Philadelphia,  Trenton  and  Connecting  Railroad,  basanite; 
at  the  quarries  on  Frankford  Creek,  stilbite,  molybdenite,  hornblende; 
on  the  Connecting  Railroad,  wad,  earthy  cobalt ;  at  Chestnut  Hill, 
magnetite,  green  mica,  chalcopyrite,  fluorite. 

FAIBMOUNT  WATER- WORKS. — In  the  quarries  opposite  Fainnount, 


CATALOGUE   OP   AMERICAN   LOCALITIES    OF   MINERALS.          355 

autunite !  torbernite,  crystals  of  feldspar,  beryl,  pseudomorphs  after 
beryl,  tourmaline,  albite,  wad,  menaccanite. 

GORGAS'S  and  CREASE'S  LANE.— Tourmaline,  cyanite,  staurolite, 
hornstone. 

Near  GERMANTOWN. — Black  tourmaline,  laumontite,  apatite;  York 
Road,  tourmaline,  beryl. 

HESTONVILLE. — Alunogen,  iron  alum,  ortlioclase. 

HEFT'S  MILL. — Alunogen,  tourmaline,  cyanite,  titanite. 

MANAYUNK. — At  the  soapstone  quarries  above  Manayunk,  talc, 
steatite,  chlorite,  vermiculite,  anthophyllite,  staurolite,  dolomite,  apa- 
tite, asbestus,  brown  spar,  epsomite. 

MEGARGEE'S  Paper-mill. — Staurolite,  titanic  iron,  hyalite,  apatite, 
green  mica,  iron  garnets  in  great  abundance. 

MCKINNEY'S  QUARRY,  on  Rittenhouse  Lane.— Feldspar,  apatite,  stil- 
Ute,  natrolite,  heulandite,  epidote,  hornblende,  erubescite,  malachite. 

SCHUYLKILL  FALLS. — Chabazite,  titanite,  fluorite,  epidote,  musco- 
vite,  tourmaline,  prochlorite. 

SCHUYLKILL  CO.— TAMAQUA,  near  POTTSVILLE,  in  coal  mines.— 
Kaolinite. 

YORK  CO. — Bornite,  rutile  in  slender  prisms  in  granular  quartz. 

DELAWARE. 

NEWCASTLE  CO.  — BRANDYWINE  SPRINGS.—  Bucholzite,  fbrolite 
abundant,  sahlite,  pyroxene ;  Brandywine  Hundred,  muscovite,  en- 
closing reticulated  magnetite. 

DIXON'S  FELDSPAR  QUARRIES,  six  miles  N.  W.  of  Wilmington 
(quarries  worked  for  the  manufacture  of  porcelain). — Adularia,  albite, 
oligoclase,  beryl,  apatite,  cinnamon-stone  !  !  magnesite,  serpentine,  as- 
bestus, black  tourmaline  !  (rare),  indicolite  !  (rare),  sphene  in  pyroxene, 
cyanite. 

DUPONT'S  POWDER  MILLS.—"  Hypersthene." 

EASTBURN'S  LIMESTONE  QUARRIES,  near  the  Pennsylvania  line. — 
Tremolite,  Ironzite. 

QUARRYVILLE.— Garnet,  spodumene,  fibrolite. 

Near  NEWARK,  on  the  railroad. — Sphserosiderite  on  drusy  quartz, 
jasper  (ferruginous  opal),  cryst.  spathic  iron  in  the  cavities  of  cellular 
quartz. 

WAY'S  QUARRY,  two  miles  south  of  Centreville. — Feldspar  in  fine 
cleavage  masses,  apatite,  mica,  deweylite,  granular  quartz. 

WILMINGTON.— In  Christiana  quarries,  metattoidal  diallage. 

KENNETT  TURNPIKE,  near  Centreville. — Cyanite  and  garnet. 

HARTFORD  CO.— Deweylite. 

KENT  CO.— Near  MIDDLETOWN,  in  Wm.  Folk's  marl  pits.— Fm- 
anite  ! 

On  CHESAPEAKE  AND  DELAWARE  CANAL.— Retinasphalt,  pyrite, 
amber. 

SUSSEX  CO.— Near  CAPE  HENLOPEN.— Vivianite. 

MARYLAND. 

BALTIMORE  (Jones's  Falls,  If  mile  from  B.). — Chabazite  (haydenite), 
heulandite  (beaumontite  of  Levy),  pyrite,  lenticular  carbonate  of  iron, 
mica,  stilbite. 


356  SUPPLEMENT   TO    DESCRIPTIONS    OP    SPECIES. 

Sixteen  miles  from  Baltimore,  on  the  Gunpowder. — Graphite. 

Twenty-three  miles  from  13.,  on  the  Gunpowder. — Talc. 

Twenty-five  miles  from  B.,  on  the  Gunpowder. — Magnetite,  sphene, 
pycnite. 

Thirty  miles  from  B.,  in  Montgomery  Co.,  on  farm  of  S.  Eliot. — 
Gold  in  quartz. 

Eight  to  twenty  miles  north  of  B.,  in  limestone. — Tremolite,  augite, 
pyrite,  brown  and  yellow  tourmaline. 

Fifteen  miles  north  of  B. — Sky-blue  chalcedony  in  granular  lime- 
stone. 

Eighteen  miles  north  of  B.,  at  Scott's  mills. — Magnetite,  cyanite. 

BAKE  HILLS. — Chromite,  asbestus,  tnmolite,  talc,  hornblende,  ser- 
pentine, chalcedony,  meerschaum,  baltimorite,  chalcopyrite,  mag- 
netite. 

CAPE  SABLE,  near  Magothy  R. — Amber,  pyrite,  alum  slate. 

CARROLL  Co. — Near  Sykesville,  Liberty  Mines,  gold,  magnetite, 
pyrite  (octahedrons),  chalcopyrite,  linnseite  (carrollite) ;  at  Patapsco 
Mines,  near  Finksburg,  bornite,  malachite,  siegenite,  linnceite,  reming- 
tonite,  magnetite,  chalcopyrite ;  at  Mineral  Hill  mine,  bornite,  chalco- 
pyrite, ore  of  nickel  (see  above),  gold,  magnetite. 

CECIL  Co.,  north  part. — Chromite  in  serpentine. 

COOPTOWN,  Harford  Co.— Olive-colored  tourmaline,  diallage,  talc  of 
green,  blue,  and  rose  colors,  lirniform  asbestus,  chromite,  serpentine. 

DEER  CREEK. — Magnetite!  in  chlorite  slate. 

FREDERICK  Co. — Old  Liberty  mine,  near  Liberty  Town,  black  cop- 
per, malachite,  chalcocite,  specular  iron  ;  at  Dollyhyde  mine,  bornite, 
chalcopyrite,  pyrite,  argentiferous  galenite  in  dolomite. 

MONTGOMERY  Co. — Oxide  of  manganese. 

SOMERSET  and  WORCESTER  Cos.,  north  part. — Bog-iron  ore,  mvi- 
anite. 

ST.  MARY'S  RIVER. — Gypsum!  in  clay. 

PYLESVILLE,  Harford  Co. — Asbestus  mine. 

VIRGINIA,  WEST  VIRGINIA,  AND  DISTRICT  OF  COLUMBIA. 

ALBEMABLE  Co.,  a  little  west  of  the  Green  Mts. — Steatite,  graphite, 
galenite. 

AMHERST  Co. — Along  the  west  base  of  Buffalo  Ridge,  copper  ores; 
on  N.  W.  slope  of  Friar  Mtn.,  allanite,  magnetite,  zircon,  sipylite. 

AUGUSTA  Co. — At  Weyer's  (or  Weir's)  cave,  sixteen  miles  north- 
east of  Staunton,  and  eighty -one  miles  northwest  of  Richmond,  cal- 
cite,  stalactites. 

BLCKINCHAM  Co. — Gold  at  Garnett  and  Moseley  mines,  also,  pyrite, 
pyrrhotite,  calcite,  garnet ;  at  Eldridge  mine  (now  London  and  Vir- 
ginia mines)  near  by,  and  the  Buckingham  mines  near  Maysville,  gold, 
auriferous  pyrite,  chalcopyrite,  tennantite,  barite ;  cyanite,  tourmaline, 
actinolite. 

CHESTERFIELD  Co. — Near  this  and  Richmond  Co.,  bituminous  coal, 
native  coke. 

CULPEPPER  Co.,  on  Rapidan  River. — Gold,  pyrite. 

FRANKLIN  Co. — Grayish  steatite. 

FAUQUIER  Co.,  Barnett's  mills. — Asbestus,  gold  mines,  barite,  cat- 
cite. 


CATALOGUE   OF   AMERICAN  LOCALITIES   OF  MINERALS.  357 

FLUVANNA  Co. — Gold  at  Stockton's  mine ;  also  tetradymite,  at 
"  Tellurium  mine." 

PHENIX  COPPER  MINES. — Chalcopyrite,  etc. 

GEORGETOWN,  D.  C. — Rutile. 

GOOCHLAND  Co. — Gold  mines  (Moss  and  Busby's). 

HARPER'S  FERRY,  on  both  sides  of  the  Potomac. — Thuringite  (owen- 
ite)  with  quartz. 

JEFFERSON  Co.,  at  Shepherdstown. — Fluor. 

KANAWHA  Co. — At  Kauavvha,  petroleum,  brine  springs,  cannel  coal. 

LOUDON  Co. —  Tabular  quartz,  drase,  pyrite,  talc,  chlorite,  soapstone, 
asbestus,  chromite,  actinolite,  quartz  crystals  ;  micaceous  iron,  boruite, 
malachite,  epidote,  near  Leesburg  (Potomac  mine). 

LOUISA  Co. — Walton  gold  mine,  gold,  pyrite,  chalcopyrite,  argen- 
tiferous galenite,  siderite,  blende,  anglesite ;  boulangerite,  blende  (at 
Tinder's  mine). 

NELSON  Co. — Galenite,  chalcopyrite,  malachite. 

ORANGE  Co. — Western  part,  Blue  Ridge,  specular  iron  ;  gold  at  the 
Orange  Grove  and  Vaucluse  gold  mines,  worked  by  the  "  Freehold  " 
and  "  Liberty  "  Mining  Companies. 

ROCKBRIDGE  Co.,  three  miles  southwest  of  Lexington. — Barite, 
etrengite. 

SIIENANDOAH  Co..  near  Woodstock.— Fluorite. 

MT.  ALTO,  Blue  Ridge. — Argillaceous  iron  ore. 

SPOTTSYLVANIA  Co.,  two  miles  northeast  of  Chancellorville.— Cy- 
anite ;  gold  mines  at  the  junction  of  the  Rappahannock  and  Rapidan  ; 
on  the  Rappahanuock  (Marshall  mine);  Whitehall  mine,  affording 
also  tedradymite. 

STAFFORD  Co.,  eight  or  ten  miles  from  Falniouth. — Micaceous  iron, 
gold,  tedradymite,  silver,  galenite,  vivianite. 

WASHINGTON  Co.,  eighteen  miles  from  Abingdon.—  Rock  salt  with 
gypsum. 

WYTHE  Co.  (Austin's  mines). — Cerussite,  minium,  plumbic  ochre, 
blende,  calamine,  galenite,  graphite. 

On  the  Potomac,  twenty-five  miles  north  of  Washington  City.—  Na- 
tive sulphur  in  gray  compact  limestone. 


NORTH  CAROLINA. 


ASHE  Co. — Malachite,  chalcopyrite. 

BUNCOMBE  Co.  (now  called  Madison  Co.) — Corundum  (from  a  boul- 
der), margarite,  corundophilite,  garnet,  chromite,  barite,  fluoi*ite,  ru- 
tile,  iron  ores,  manganese,  zircon  ;  at  Swananoa  Gap,  cyanite. 

BURKE  Co. — Gold,  monazite,  zircon,  beryl,  corundum,  gar  net,  sphene, 
graphite,  iron  ores,  tetradymite,  montanite  (hydrous  bismuth  tellurate). 

CABARRUS  Co. — Phenix  Mine,  gold,  barite,  chalcopyrite,  auriferous 
pyrite,  -quartz  pseudomorph  after  barite,  tetradymite,  montanite  ;  Pi- 
oneer mines,  gold,  limonite,  pyrolusite,  barnhardite,  wolfram,  scheelite, 
cuprotungstite,  tungstite,  diamond,  chrysocolla,  chalcocite,  molybde- 
nite, chalcopyrite,  pyrite ;  White  mine,  needle  ore,  chalcopyrite,  ba- 
rite ;  Long  and  Muse's  mine,  argentiferous  galenite,  pyrite,  chalcopy- 
rite, limonite  ;  Boger  mine,  tetradymite  ;  Fink  mine,  valuable  copper 
ores ;  Mt.  Makins,  tetrahedrite,  magnetite,  talc,  blende,  pyrite,  prous- 
tite,  galenite  ;  Bangle  mine,  scheelite. 


358  SUPPLEMENT   TO   DESCRIPTIONS  OP    SPECIES. 

CALDWELL  Co. — Chromite. 

CHATHAM  Co. — Mineral  coal,  pyrite,  cliloritoid. 

CHEROKEE  Co. — Iron  ores,  gold,  galenite,  corundum,  rutile,  cyanite, 
dainonite. 

CLEVELAND  Co. — White  Plains,  quartz,  crystals,  smoky  quartz,  tour- 
maline, rutile  in  quartz. 

CLAY  Co. — At  the  Cullakenee  mine  and  elsewhere,  corundum  (pink), 
zoisite,  tourmaline,  margarite,  willcoxite,  dudleyite. 

DAVIDSON  Co. — King's,  now  Washington  mine,  native  silver,  cerus- 
site,  anglesite,  scheelite,  pyromorphite,  galenite,  blende,  malachite, 
black  copper,  wavellite,  garnet,  stilbite  ;  five  miles  from  Washington 
mine,  on  Faust's  .farm,  gold,  tetradymite,  oxide  of  bismuth  and  tellu- 
rium, montanite,  chalcopyrite,  limonite,  spathic  iron,  epidote  ;  near 
Squire  Ward's,  gold  in  crystals,  electrum. 

FRANKLIN  Co. — At  Partiss  mine,  diamonds. 

GASTON  Co. — Iron  ores,  corundum,  margarite ;  near  Crowder's  Moun- 
tain (in  what  was  formerly  Lincoln  Co.),  lazulite,  cyanite,  garnet,  gra- 
phite ;  also  twenty  miles  northeast,  near  south  end  of  Clubb's  Moun- 
tain, lazulite,  cyanite,  talc,  rutile,  topaz,  pyrophyllite  ;  King's  Moun- 
tain (or  Briggs)  mine,  native  tellurium,  altaite,  tedradymite,  monta- 
nite. 

GUILFORD  Co. — McCulloch  copper  and  goldmine,  twelve  miles  from 
Greensboro',  gold,  pyrite,  chalcopyrite  (worked  for  copper),  quartz,  sid- 
erite ;  copper  ore  at  the  old  Fentress  mine  ;  at  Deep  River,  compact 
pyrophyllite  (worked  for  slate-pencils), 

HAYWOOD  Co. — Corundum,  margarite,  damourite. 

HENDERSON  Co. — Zircon,  sphene  (xanthitane). 

JACKSON  Co. — Alunogen  ?  at  Smoky  Mountain  ;  at  Webster,  serpen- 
tine, chromite,  genthite,  chrysolite,  talc ;  Hoghalt  Mountain,  pink  co- 
rundum, margarite,  tourmaline. 

LINCOLN  Co.— Diamond  ;  at  Randleman's,  amethyst,  rose  quartz. 

MACON  Co.— Franklin,  Culsagee  mine,  corundum,  spinel,  diaspore, 
tourmaline,  damourite,  prochlorite,  cnlsageeite,  kerrite,  maconite. 

MCDOWELL  Co. — Brookite,  monazite,  corundum  in  small  crystals, 
red  and  white,  zircons,  garnet,  beryl,  sphene,  xenotime,  rutile,  elastic 
sandstone,  iron  ores,  pyromelane,  tetradymite,  montanite. 

MADISON  Co. — Twenty  miles  from  Asheville,  corundum,  margarite, 
chlorite. 

MECKLENBURG  Co. — Near  Charlotte  (Rhea  and  Cathay  mines)  and 
elsewhere,  chalcopyrite,  gold;  chalcotrichite  at  McGinn's  mine;  barn- 
hardtite  near  Charlotte  ;  pyrophyllite  in  Cotton  Stone  Mountain,  dia- 
mond ;  Flowe  mine,  scheelite,  wolframite  ;  Todd's  Branch,  monazite. 

MITCHELL  Co. — At  the  Wiseman  mica  mine,  muscovite  samarskite, 
hatchettolite,  euxenite,  columbite,  rogersite,  uraninite,  gummite,  ura- 
conite,  torbernite,  autunite  ;  at  Grassy  Creek  mine,  muscomte,  samara- 
kite. 

MONTGOMERY  Co. — Steele's  mine,  ripidolite,  albite. 

MOORE  Co. — Carbon  ton,  compact  pyrophyllite. 

ROWAN  Co.— Gold  Hill  mines,  thirty-eight  miles  northeast  of  Char- 
lotte,  and  fourteen  from  Salisbury,  gold,  auriferous  pyrite ;  ten  miles 
from  Salisbury,  feldspar  in  crysteils.bismuthmite. 

RANDOLPH  Co.— Pyrophyllite. 

RUTHERFORD  Co.— Gold, graphite,  bismuthic  gold,  diamond,  euclase, 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF  MINERALS.          359 

pseudomorphous  quartz?  chalcedony,  corundum  in  small  crystals,  epi- 
dote,  pyrope,  brookite,  zircon,  monazite,  rutherfordite,  samarskite, 
quartz  crystals,  itacolumyte  ;  on  the  road  to  Cooper's  Gap,  cy anile. 

STOKES  and  SURKY  Cos. — Iron  ores,  graphite. 

UNION  Co. — Lemmond  gold  mine,  eighteen  miles  from  Concord  (at 
Stewart's  and  Moore's  mine),  gold,  quartz,  blende,  argentiferous  gale- 
nite  (containing  29 '4  oz.  of  gold  and  b6'5  oz.  of  silver  to  the  ton,  Genth), 
pyrite,  some  chalcopyrite. 

YANCEY  Co. — Iron  ores,  amianthus,  cliromite,  garnet  (spessartite), 
samarskite,  columbite. 

SOUTH  CAROLINA. 

ABBEVILLE  DIST. — Oakland  Grove,  gold  (Dora  mine),  galenite,  pyro- 
morphite,  amethyst,  garnet. 

ANDERSON  DIST. — At  Pendleton,  actinolite,  galenite,  kaolin,  tourma- 
line. 

CHARLESTON. —Selenite. 

CHEOWEE  VALLEY.— Galenite,  tourmaline,  gold. 

CHESTERFIELD  DIST. — Gold  (Brewer's  mine),  talc,  chlorite,  pyrophyJ- 
lite,  pyrite,  native  bismuth,  bismuth  carbonate,  red  and  yellow  ochre, 
whetstone,  enargite. 

DARLINGTON. — Kaolin. 

EDGEFIELD  DIST. — Psilomelane, 

GREENVILLE  DIST.— Galenite,  pyromorphite,  kaolin,  chalcedony  in 
buhrstone,  beryl,  plumbago,  epidote,  tourmaline. 

KERSHAW  DIST. — Rutile. 

LANCASTER  DIST. — Gold  (Hale's  mine),  talc,  chlorite,  cyanite,  ita- 
columyte, pyrite  ;  gold  also  at  Blackmail's  mine,  Massey's  mine, 
Ezell's  mine. 

LAURENS  DIST.— Corundum,  damourite. 

NEWBERRY  DIST.— Leadhillite. 

PICKENS  DIST. — Gold,  manganese  ores »  kaolin, 

HIGHLAND  DIST. — Chiastolite,  novaculite. 

SPARTANBURG  DIST. — Magnetite,  chalcedony,  hematite  ;  at  the  Cow- 
pens,  limonite,  graphite,  limestone,  copperas ;  Morgan  mine,  leadhil- 
lite,  pyromorphite,  cerussite. 

SUMTER  DIST. — Agate. 

UNION  DIST. — Fairforest  gold  mines,  pyrite,  chalcopyrite. 

YORK  DIST. — Limestones,  whetstones,  witherite,  barite,  tetrady- 
mite. 

GEORGIA. 

BURKE  AND  SCRIVEN  Cos.— Hyalite. 

CHEROKEE  Co. — At  Canton  Mine,  chalcopyrite,  galenite,  claustha- 
lite,  plumbogummite,  hitchcockite,  arsenopyrite,  lanthanite,  harrisite, 
cantonite,  pyromorphite,  automolite,  zine,  staurolite,  cyanite ;  at  Ball- 
Ground,  spodumene. 

CLARK  Co.,  near  Clarksville.— Gold,  xenotime,  zircon,  rutile,  cyanite, 
hematite,  garnet,  quartz. 

DADE  Co. — Halloysite,  near  Rising  Fawn. 

FANNIN  Co.— Staurolite  !  chalcopyrite. 


360  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

HABERSHAM  Co. — Gold,  pyrite,  chalcopyrite,  galenite,  hornblende, 
garnet,  quartz,  kaolinite,  soapstone,  chlorite,  rutile,  iron  ores,  tourma- 
line, staurolite,  zircon. 

HALL  Co. — Gold,  quartz,  kaolin,  diamond. 

HANCOCK  Co.  —Agate,  chalcedony. 

HEARD  Co. — Molubdite,  quartz. 

LEE  Co. — At  the  Chewacla  Lime  Quarry,  dolomite,  barite,  quartz 
crystals. 

LINCOLN  Co. — Lazulite  !  !  rutile!  !  hematite,  cyanite,  manaccanite, 
pyrophyllite,  gold,  itacolumyte  rock. 

LOWNDES  Co. — Corundum. 

LUMPKIN  Co. — At  Field's  gold  mine,  near  Dahlonega,  gold,  tetrady- 
mite,  pyrrhotite,  chlorite,  menaccanite,  allanite,  apatite. 

RABUN  Co. — Gold,  ckalcopyrite. 

SPAULDING  Co. — Tetradymite. 
.  WASHINGTON  Co.,  near  Saundersville. —  Wavellite,  fire  opal. 

ALABAMA. 

BENTON  Co. — Antimonial  lead  ore  (boulangerite  ?) 

BIBB  Co.,  Centreville. — Iron  ores,  marbl  ,  barite,  coal,  cobalt. 

CHAMBERS  Co. — Near  La  Fayette,  steatite,  garnets,  actinolite,  chlo- 
rite ;  east  of  Oak  Bowery,  steatite. 

CHILTON  Co — Muscovite,  graphite,  limonite. 

CLEBURNE  Co. — At  Arbacoochee  mine,  gold,  pyrite,  and  three  miles 
distant  cyanite,  garnets  ;  at  Wood's  min  black  copper,  azurite,  chalco- 
pyrite, pyrite. 

CLAY  Co. — Steatite  ;  near  Delta  and  Ashland,  muscovite. 

Coos  A  Co. — Tantalite,  gold,  muscovite. 

RANDOLPH  Co. — Gold,  pyrite,  tourmaline,  muscovite  ;  at  Louina, 
porcelain  clay,  gar  et. 

TALLADEGA  C..—  Limonite. 

TALLAPOOSA  Co.  at  Dudley ville.— Corundum,  margarite,  ripidolite, 
spinel,  tourmaline,  actinolite,  steatite,  asbestus,  chrysolite,  damourite, 
corundum  altered  to  tourmaline  (crystals  of  the  latter  containing  a 
nucleus  of  the  former)  and  also  other  pseudomorphs,  including,  at 
Dudleyville,  dudleyite. 

TUSKALOOSA  Co. — Goal,  galenite,  pyrite,  vivianite,  limonite,  calcite, 
dolomite,  cyanite,  steatite,  quartz  crytals,  manganese  ores. 

FLORIDA. 

NEAR  TAMPA  BAY. — Limestone,  sulphur  springs,  chalcedony, 
carnelian,  agate,  silicified  shells  and  corals. 

KENTUCKY. 

ANDERSON  Co.  —Galenite,  barite. 
CLINTON  Co. — Geodes  of  quartz. 
CBITTENDEN  Co. — Galenite,  fluorite,  calcite. 

EDMONDSON  Co. — At  Mammoth  Cave,  gypsum,  rosettes  !  calcite,  sta- 
lactites, nitre,  epsomite. 


CATALOGUE   OF   AMERICAN   LOCALITIES  OF   MINERALS.          361 

FAYETTE  Co. — Six  miles  N.  E.  of  Lexington,  galenite,  barite, 
witherite,  blende. 

LIVINGSTON  Co. ,  near  the  line  of  Union  Co. — Galenite,  chalcopyrite, 
large  vein  of  fluorite. 

MERCER  Co. — At  McAfee,  fluorite,  pyrite,  calcite,  barite,  celestite. 

OWEN  Co. — Galenite,  barite. 

TENNESSEE. 

BROWN'S  CREEK.— Galenite,  blende,  barite,  celestite. 

CARTER  Co.,  foot  of  Roan  Mt. — Sahlite,  magnetite. 

CLAIBORNE  Co. — Calamine,  galenite,  sinithsonite,  chlorite,  steatite, 
magnetite. 

COCKE  Co.,  near  Bush  Creek. — Cacoxenite?  kraurite,  iron  sinter, 
stilpnosiderite,  brown  hematite. 

DAVIDSON  Co.-  Selenite,  with  granular  and  snowy  gypsum,  or  ala- 
baster, crystallized  and  compact  anhydrite,  jtuorite  in  crystals  ?  calcite 
in  crystals.  Near  Nashville,  blue  celestite  (crystallized,  fibrous,  and 
radiated),  with  barite  in  limestone.  Haysboro',  galenite,  blende,  with 
barite  as  the  gangue  of  the  ore. 

DICKSON  Co.— Manganite. 

JEFFERSON  Co. — Calamine,  galenite,  fetid  barite. 

KNOX  Co. — Magnesian  limestone,  native  iron,  variegated  marbles! 

MAURY  Co. — Wavellite  in  limestone. 

MORGAN  Co. — Epsom  salt,  nitrate  of  lime. 

POLK  Co.,  Ducktown  mines,  southeast  corner  of  State. — Melaconite, 
chalcopyrite,  pyrite,  native  copper,  bornite,  rutile,  zoisite,  galenite,  har- 
risite,  alisonite,  blende,  pyroxene,  tremolite,  sulphates  of  copper  and 
iron  in  stalactites,  allophane,  rahtite,  chalcocite  (ducktownite),  chal- 
cotrichite,  azurite,  malachite,  pyrrhotite,  limonite. 

ROAN  Co.,  easterly  declivity  of  Cumberland  Mts.— Wavellite  in 
limestone. 

SEVIER  Co.,  in  caverns. — Epsomite,  soda  alum,  nitre,  nitrate  of 
calcium,  breccia  marble. 

SMITH  Co.— Fluorite. 

SMOKY  MT.,  on  declivity. — Hornblende,  garnet,  staurolite. 

WHITE  Co.— Nitre. 

OHIO. 

BAINBRIDGE  (Copperas  Mt.,  a  few  miles  east  of  B.). — Calcite,  barite, 
pyrite,  copperas,  alum. 

CANFIELD. — Gypsum  ! 

DUCK  CREEK,  Monroe  Co. — Petroleum. 

LAKE  ERIE. — Strontian  Island,  celestite!  Put-in-Bay  Island,  celestite! 
sulphur!  calcite. 

LIVERPOOL.  — Petroleum. 

MARIETTA. — Argillaceous  iron  ore  •  iron  ore  abundant  also  in  Scioto 
and  Lawrence  Cos. 

OTTAWA  Co. — Gypsum. 

POLAND. —Gypsum  ! 


362  SUPPLEMENT  TO  DESCRIPTIONS  OP   SPECIES. 

MICHIGAN. 

BREST  (Monroe  Co.). — Calcite,  amethystine  quartz,  apatite,  celestite. 

GRAND  RAPIDS. — ISelenite,  fib.  and  granular  gypsum,  calcite,  dolomite, 
anhydrite. 

LAKE  SUPERIOR  MINING  REGION. — The  four  principal  regions  are 
Keweenaw  Point,  Isle  Royale,  the  Ontonagon,  and  Portage  Lake. 
The  mines  of  Keweenaw  Point  are  along  two  ranges  of  elevation,  one 
known  as  the  Greenstone  Range,  and  the  other  as  the  Southern  or 
Bohemian  Range  (Whitney).  The  copper  occurs  in  the  trap  or  amyg- 
daloid, and  in  the  associated  conglomerate.  Rat-foe  copper!  native 
silver!  chalcopyrite,  horn  silver,  tetrahedrite,  manganese  ores,  epi- 
dote,  prchnite,  laumontite,  datolite,  heulandite,  orthoclase,  analcite,  cha- 
bazite,  compact  datolite,  chrysocolla,  mcsotype  (Copper  Falls  mine), 
leonhardite  (ib.),  analcite  (ib.),  apophyllite  (at  Cliff  mine),  wollastonite 
(ib.),  calcite,  quartz  (in  crystals  at  Minnesota  mine),  compact  datolite, 
orthoclase  (Superior  mine),  saponite,  melaconite  (near  Copper  Harbor, 
but  exhausted),  chrysocolla ;  on  Chocolate  River,  galenite  and  sul- 
phide of  copper  ;  chalcopyrite  and  native  copper  at  Presq'lsle  ;  at 
Albion  mine,  domeykite ;  at  Prince  Vein,  barite,  calcite  amethyst ;  at 
Albany  and  Boston  mine,  Portage  Lake,  prehnite,  analcite,  orthoclase, 
cuprite  ;  at  Sheldon  location,  domeykite,  whitneyite,  algodonite  ;  Quincy 
mine,  calcite,  compact  datolite.  At  the  Spur  Mountain  iron  mine 
(magnetite),  chlorite  pseudomorph  after  garnet ;  Isle  Royale,  datolite, 
prehnite. 

MARQUETTE. — Manganite,  galenite ;  twelve  miles  west  at  Jackson 
Mt.,  and  other  mines,  hematite,  limonite,  gbthite!  magnetite,  jasper. 

MONROE. — Aragonite,  apatite. 

POINT  AUX  PEAUX  (Monroe  Co.) — Amethystine  quartz,  apatite,  celes- 
tite, calcite. 

SAGINAW  BAY. — At  Alabaster,  gypsum. 

STONY  POINT  (Monroe  Co.) — Apatite,  amethystine  quartz,  celestite, 
calcite. 

ILLINOIS. 

GALLATIN  Co.,  on  a  branch  of  Grand  Pierre  Creek,  sixteen  to  thirty 
miles  from  Shawneetown,  down  the  Ohio,  and  from  half  to  eight 
miles  from  this  river. —  Violet  fiuorite!  in  carboniferous  limestone, 
barite,  galenite,  blende,  brown  iron  ore. 

HANCOCK  Co. — At  Warsaw,  quartz  geodes  containing  calcite !  chal- 
cedony, dolomite,  blende  !  brown  spar,  pyrite,  aragonite,  gypsum,  bitu- 
men. 

HARDIN  Co. — Near  Rosiclare,  calcite,  galenite,  blende  ;  five  miles 
back  from  Elizabethtown,  bog  iron  ;  one  mile  north  of  the  river,  be- 
tween Elizabethtown  and  Rosiclare,  nitre. 

Jo  DAVIESS  Co.— At  Galena,  galenite,  calcite,  pyrite,  blende ;  at  Mars- 
den's  diggings,  galenite  !  blende,  cerussite,  marcasite  in  stalactitic  form* 
pyrite. 

JOLIET.  — Marble. 

QUINCY.— Calcite!  pyrite. 

SCALES  MOUND. — Barite,  pyrite. 


CATALOGUE  OF   AMERICAN   LOCALITIES   OF  MINERALS.          363 
INDIANA. 

LIMESTONE  CAVERNS  ;  Corydon  Caves,  etc. — Epsom  salt. 

In  most  of  the  southwest  counties,  pyrite,  iron  sulphate,  and  feather 
alum;  on  Sugar  Creek,  pyrite  and  iron  sulphate  ;  in  sandstone  of  Lloyd- 
Co.,  near  the  Ohio,  gypsum  ;  at  the  top  of  the  blue  limestone  forma 
tion,  brown  spar,  calcite. 

LAWRENCE  Co. — Spice  Valle,  kaolinite  (=indianaite). 

MINNESOTA. 

NORTH  SHORE  OF  L.  SUPERIOR  (ranjre  of  hills  running  nearly  north 
east  and  southwest,  extending  from  Fond  du  Lac  Superieure  to  thf 
Kamanistiqueia  River  in  Upper  Canada). — Scolecite,  apophyllite.  preh- 
nite,  stilbite,  laumontite,  heulandite,  harmotome,  thomsonite,  fluorite, 
barite,  tourmaline,  epidote,  hornblende,  calcite,  quartz  crystals,  pyrite, 
magnetite,  steatite,  blende,  black  oxide  of  copper,  malachite,  native 
copper,  chalcopyrite,  amethystine  quartz,  ferruginous  quartz,  ehalce- 
dony,  carnelian,  agate,  drusy  quartz,  hyalite?  fibrous  quartz,  jasper, 
prase  (in  the  debris  of  the  lake  shore),  dogtooth  spar,  augite,  native 
silver,  spodumene?  chlorite  ;  between  Pigeon  Point  and  Fond  du  Lac, 
near  Baptism  River,  saponite  (thalite)  in  amygdaloid. 

KETTLE  RIVER  TRAP  RANGE.— Epidote,  nail-head  calcite,  amethys- 
tine quartz,  calcite,  undetermined  zeolites,  saponite. 

STILL  WATER. — Blende. 

FALLS  OF  THE  ST.  CROIX. — Malachite,  native  copper,  epidote,  nail- 
head  spar  (calcite). 

RAINY  LAKE. — Actinolite,  tremolite,  fibrous  hornblende,  garnet,  py- 
rite, magnetite,  steatite. 

WISCONSIN. 

BIG  BULL  FALLS  (near). — Bog  iron. 

BLUE  MOUNDS.— Cerussite. 

HAZEL  GREEN. — Calcite. 

LAC  DU  FLAMBEAU  R. — Garnet,  cyanite. 

LEFT-HAND  R.  (near  small  tributary). — Malachite,  chalcocite,  native 
copper,  cuprite,  malachite,  epidote,  chlorite?  quartz  crystals. 

LINDEN. — Oalenite,  smithsonite,  hydrozindte. 

MINERAL  POINT  and  vicinity. — Copper  and  lead  ores,  chrysocolla, 
azuritef  chalcopyrite,  malachite,  galenite.  cerussite,  anglesite,  blende, 
py)"ite,  barite,  calcite,  marcasite,  smithsonite!  (including  pseudomorphs 
after  calcite  and  blende),  (so-called  "  dry-bone "),  calamine,  bornite, 
hydrozincite. 

MONTREAL  RIVER  PORTAGE. — Galenite  in  gneissoid  granite. 

SAUK  Co. — Hematite,  malachite,  chalcopyrite. 

SHULLSBURG. — Galenite !  blende,  pyrite  ;  at  Emmet's  digging,  ga- 
lenite and  pyrite. 

IOWA. 

Du  BUQUE  LEAD  MINES,  and  elsewhere. — Galenite  f  calcite,  blende, 
black  oxide  of  manganese  ;  at  Ewing's  and  Sherard's  diggings,  smith' 


364  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

sonite,  calami ne  ;  at  Des  Moines,  quartz  crystals,  selenite  ;  Makoqueta 
R.,  limonite  ;  near  Durango,  galenite. 

CEDAU  RIVER,  a  branch  of  the  Des  Moines. — Selenite  in  crystals,  in 
the  bituminous  shale  of  the  coal  measures  ;  also  elsewhere  on  the  Des 
Moines,  gypsum  abundant  ;  argillaceous  iron  ore,  spathic  iron  ;  cop- 
peras in  crystals  on  the  Des  Moines,  above  the  mouth  of  Saap  and  else- 
where, pyrite,  blende. 

FORT  DODGE. — Celestite. 

MAKOQUETA. — Hematite. 

NEW  GALENA. — Octahedral  galenite,  anglesite. 


MISSOURI. 

For  the  distribution  of  the  lead  mines  see  page  147.  The  number 
of  minerals  associated  with  the  lead  ore  varies  greatly  in  the  different 
lead  regions.  Mine  la  Motte.  and  some  old  openings  in  Madison  C'o., 
are  peculiar  in  affording  cobalt  and  nickel  ores  abundantly.  At  Granby 
and  other  mines  the  chief  zinc  ore  is  calamine,  or  the  silicate  of  zinc, 
while  in  the  mines  of  Central  and  Southwest  Missouri  it  is  compara- 
tively rare,  and  smithsonite  is  the  prominent  ore — as  is  the  case  in. 
Wisconsin  ;  yet  calamine  is  the  most  abundant  zinc  ore  in  the  State. 
As  stated  by  A.  Schmidt,  the  zinc  ore,  in  each  case,  is  found  as  a  sec- 
ondary product  to  sphalerite  (blende) ;  the  cerussite  often  coats  the 
galenite,  or  has  its  forms,  indicating  thus  its  source  ;  the  limonite  is 
also  secondary,  and  has  come  in  mainly  through  the  oxidation  of  py- 
rite. At  the  Granby  mines,  the  calamine  is  called,  among  the  miners, 
"  Black  Jack  ;  "  blende,  "  Resin  Jack  ;  "  a  white  massive  smithsonite, 
"  White  Jack  ;"  and  the  cerussite  is  the  "  Dry  Bone  ;  "  thus  departing 
from  ordinary  miners'  usage.  Gold  has  been  found  in  the  drift  sands 
of  Northern  Missouri  (Broadhead). 

ADAIR  Co. — Gothite  in  calcite. 

BARTON  Co. — Pickeringite  as  an  effloresence  on  sandstone. 

CHARITON  Co. — Near  Salisbury,  gypsum  (selenite)  in  coal  beds. 

COLE  Co. — At'  Old  Circle  Diggings  and  elsewhere,  barite!  galenite, 
chalcopyrite,  malachite,  azurite,  pyrite,  calcit*,  calamine,  sphalerite. 

COOPER  Co. — Collins  Mine,  malachite  with  azurite,  etc. 

DADE  Co. — Smithsonite. 

FRANKLIN  Co. — Cove  Mines,  anglesite,  galenite,  cerussite,  barite. 

IRON  Co. — At  Pilot  Knob  and  Shepherd  Mountain,  hematite,  mag- 
netite, limonite,  manganese  oxide,  bog  manganese. 

JASPER  Co.  (adjoins  S.  E.  Kansas). — At  Joplin  Mines,  galena  !  spha- 
lerite, pyrite,  cerussite,  calamine,  dolomite,  bitumen. 

JEFFERSON  Co. — At  Valle's,  galenite  !  cerussite,  anglesite,  calamine, 
smithsonite,  sphalerite,  hydrozincite,  chalcopyrite,  malachite,  azurite, 
pyrite,  barite,  witherite,  limonite.  At  Fruinet  mines,  8.^  miles  from 
DeSoto  R.  R.  station,  galena,  barite  !  smithsonite  !  pyrite,  limnite. 

MADISON  Co. — At  Mine  la  Motte,  gulenite!  cerussite!  siegenite  (nickel- 
linnaeite),  smaltite,  asbolite  (earthy  black  cobalt  ore),  bog  manganese, 
chalcopyrite,  malachite,  caledonite,  plumbogummite,  wolframite. 

MORGAN  Co. — At  Cordray  Diggings,  galena,  blende,  barite. 

NKWTON  Co.  (adjoins  S.  E.  Kansas). — At  Granby  Mines,  galenite! 
cerusfiitc,  calamine!  sphalerite,  smithsonite,  hydrozincite,  green-ockite 
(on  sphalerite),  pyromorphite,  dolomite,  calcite,  bitumen,  buratite. 


CATALOGUE   OF  AMERICAN  LOCALITIES   OF   MINERALS.  365 

ST.  FRANCOIS  Co  — Iron  Mountain,  hematite,  magnetite,  limonite. 

ST.  Louis  Co — Near  St.  Louis,  millerite  (in  the  Subcarboniferous 
St.  Louis  limestone,  largely  a  inagnesian  limestone)  with  calcite  !  ba- 
rite, fluorUe. 

WASHINGTON  Co. — At  Potosi,  galenite,  cerussile,  anglesite,  barite 

ARKANSAS. 

BATESVILLE. — In  bed  of  White  R.,  some  miles  above  Batesville, 
gold. 

GREEN  Co. — Near  Gainesville,  lignite. 

HOT  SPRINGS  Co. — At  Hot  Springs,  wavellite,  thuringite;  Magnet 
Cove,  brookite  !  schorlomite,  elceolite,  magnetite,  quartz,  green  coccolite, 
garnet,  apatite,  perofskite  (hydrotitanite),  rutile,  ripidolite,  thomsouite 
(ozarkite),  microcline,  cegirite,  protovermiculite. 

INDEPENDENCE  Co. — Lafferay  Creek,  psilomelane. 

LAWRENCE  Co.— Hoppe,  Bath,  and  Koch  mines,  smithsonite,  dolo 
mit<%  galenite ;  nitre. 

MARION  Co. — Wood's  mine,  smithsonite,  hydrozincite  (marionite) 
galenite  ;  Poke  bayou,  braunite? 

MONTGOMERY  Co. — Variscite. 

OUACHITA  SPRINGS.—  Quartz?  whetstones. 

PULASKI  Co.— Kellogg  mine,  10  in.  north  of  Little  Rock,  tetrahedrite. 
tennantite,  nacrite,  galenite,  blende,  quartz. 

CALIFORNIA. 

The  principal  gold  mines  of  California  are  in  Tulare,  Fresno,  Mari- 
posa,  Tuolumne,  Calaveras,  El  Dorado,  Placer,  Nevada,  Yuba,  Sierra, 
Butte,  Plumas,  Shasta,  Siskiyou,  and  Del  Norte  counties,  although 
gold  is  found  in  almost  every  county  of  the  State.  The  gold  occurs  in 
quartz,  associated  with  sulphides  of  iron,  copper,  zinc,  and  lead  ;  in 
Calaveras  and  Tuolumne  counties,  at  the  Mellones,  Stanislaus,  Golden 
Rule,  and  Rawhide  mines,  associated  with  tellurides  of  gold  and  sil- 
ver ;  it  is  also  largely  obtained  from  placer  digrings,  and  further  it  is 
found  in  beach  washings  in  Del  Norte  and  Klamath  counties. 

The  copper  mines  are  principally  at  or  near  Copperopolis,  in  Cala- 
veras County;  near  Genesee  Valley,  in  Plumas  County;  near  Low 
Divide,  in  Del  Norte  County  ;  on  the  north  fork  of  Smith's  River ;  at 
Soledad,  in  Los  Angeles  county. 

The  mercury  mines  are  at  or  near  New  Almaden  and  North  Al- 
maden,  in  Santa  Clara  County  ;  at  New  Idria  and  San  Carlos,  Monterey 
County  ;  in  San  Luis  Obispo  County  ;  at  Pioneer  mine,  and  other  locali- 
ties in  Lake  County  ;  in  Santa  Barbara  County. 

ALAMEDA  Co. — Diabolo  Range,  magnesite. 

ALPINE  Co. — Morning  Star  mine,  enargite,  stephanite,  polybasite, 
barite,  quartz,  pyrite,  tetrahedite,  pyrargyrite. 

AMADOU  Co. — At  Volcano,  chalcedony, hyalite;  Lone  Valley,  lonite; 
Fiddletown,  diamond. 

BUTTE  Co. — Cherokee  Flat,  diamond,  platinum,  iridosmine. 

CALAVERAS  Co. — Copperopolis,  chalcopyrite,  malachite,  azurite,  ser- 
pentine, picrolite,  native  copper  ;  near  Murphy's,  jasper,  opal ;  albite, 
with  gold  and  pyrite ;  Melloues  mine,  calaverite,  petzite. 


366  SUPPLEMENT   TO   DESCRIPTIONS   OP   SPECIES. 

CoNTRA-CosTA  Co. — San  Antonio,  chalcedony. 

DEL  NORTE  Co. — Crescent  City,  agate,  camel ian  ;  Low  Divide,  dial- 
copy  rite,  bornite,  malachite ;  on  the  coast,  iridosmine,  platinum,  gold, 
zircon,  diamond. 

EL  DORADO  Co. — Pilot  Hill,  chalcopyrite;  near  Georgetown,  hessite, 
from  placer  diggings  ;  Roger's  Claim,  Hope  Valley,  grossular  garnet, 
in  copper  ore  ;  Coloma,  chromite  ;  Spanish  Dry  Diggings,  gold  ;  Gran- 
ite Creek,  roscoelite,  gold  ;  Forest  Hill,  diamond  ;  Cosumues  mine, 
molybdenite. 

FKESNO  Co. — Chowchillas,  andalusite  ;  King's  River,  bornite. 

HUMBOLDT  Co.  — Cryptomorphite. 

INTO  Co. — Inyo  district,  galenite,  cerussite,  anglesite,  barite,  ataca- 
mite,  calcite,  grossular  garnet !  Surprise  Mine,  tetrahedrite  ;  Kear- 
sarge  mine,  silver  ores  ;  Cerro  Gordo,  wulfenite. 

KERN  Co. — Green  Monster  mine,  cuproscheelite. 

LAKE  Co. — Borax  Lake,  borax!  sassolite,  glauberite;  Pioneer  mine, 
cinnabar,  native  mercury,  selenide  of  mercury  ;  near  the  Geysers, 
sulphur,  hyalite ;  Redington  mine,  metacinnabarite  ;  Lower  Lake, 
chromite. 

Los  ANGELES  Co. — Near  Santa  Anna  River,  anhydrite  ;  Williams 
Pass,  chalcedony  ;  Soledad  mines,  chalcopyrite,  garnet,  gypsum  ; 
Mountain  Meadows,  garnet,  in  copper  ore. 

MARIPOSA  Co. — Chalcopyrite,  itacolumyte  ;  Centreville,  cinnabar  ; 
Pine  Tree  mine,  tetrahedrite  ;  Burns  Creek,  limonite  ;  Geyer  Gulch, 
pyrophyllite  ;  La  Victoria  mine,  azarite  !  near  Coulterville,  cinnabar, 
gold. 

MONO  Co. — Partzite  (stibiconite). 

MONTEREY  Co. — Alisal  mine,  arsenic  ;  near  Paneches,  chalcedony  ; 
New  Idria  mine,  cinnabar  ;  near  New  Idria,  chromite,  zaratite,  chrome 
garnet ;  near  Pacheco's  Pass,  stibnite. 

NAPA  Co. — Chromite. 

NEVADA  Co. — Grass  Valley,  gold!  in  quartz  veins,  with  pyrite, 
chalcopyrite,  blende,  arsenopyrite,  galenite,  quartz,  biotite  ;  near 
Truckee  Pass,  gypsum  ;  Excelsior  Mine,  molybdenite,  with  gold ; 
Sweet  Land,  pyrolusite. 

PLACER  Co. — Miner's  Ravine,  epidote  !  with  quartz,  gold. 

PLUMAS  Co. — Genesee  Valley,  chalcopyrite  ;  Hope  mines,  bornite, 
sulphur. 

SANTA  BARBARA  Co. — San  Amedio  Canon,  stibnite,  asphaltum,  bitu- 
men, maltha,  petroleum,  cinnabar,  iodide  of  mercury ;  Santa  Clara 
River,  sulphur. 

SAN  BERNARDINO  Co. — Colorado  River,  agate,  trona  ;  Temescal 
Mts. ,  cassiterite ;  Russ  District,  galenite,  cerussite  ;  Francis  mine, 
cerargyrite  ;  Slate  Range,  thenardite,  borax,  common  salt ;  San  Ber- 
nardino Mts. ,  graphites. 

SANTA  CLARA  Co. — New  Almaden,  cinnabar,  calcite,  aragonite.  ser- 
pentine, chrysolite,  quartz,  aragotite  ;  North  Almaden,  chromite  ;  Mt. 
Diabolo  Range,  magnesite,  datolite,  with  vcsuvianite  and  garnet. 

SAN  DIEGO  Co. — Carisso  Creek,  gypsum  ;  San  Isabel,  tourmaline 
orthoclase,  garnet. 

SAN  FRANCISCO  Co. — Red  Island,  pyrolusite  and  manganese  ores. 

SAN  Luis  OBISPO  Co. — Asphaltum,  cinnabar,  native  mercury, 
chromite. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OP   MINERALS.          367 

SHASTA  Co. — Near  Shasta  City,  hematite,  in  large  masses. 

SIERRA  Co. — Forest  City,  gold,  arsenopyrite,  tellurides. 

SISKIYOU  Co. — Surprise  Valley,  selenite,  in  large  slabs. 

SONOMA  Co. — Actinolite,  garnets,  chromite,  serpentine. 

TTJLARE  Co. — Near  Visalia,  magnesite,  asphaltum. 

TUOLUMNE  Co. — Tourmaline,  tremolite  ;  Sonora,  graphite ;  Tori 
Tent,  chromite  ;  Golden  Rule  mine,  petzite,  calaverite,  altaite,  hessite, 
magnesite,  tetrahcdrite,  gold  ;  Whiskey  Hill,  gold! 

TRINITY  Co. — Cassiterite,  a  single  specimen  found. 

LOWER  CALIFORNIA- 
LA  PAZ. — Cuproscheelite.    LORETTO. — Natrolite,  siderite,  selenite. 

UTAH. 

BEAVER  Co. — Bismuthinite,  bismite,  bismutite. 

TINTIC  DISTRICT. — At  the  Shoebridge  mine,  the  Dragon  mine,  and 
the  Mammoth  vein,  enargite  with  pyrite. 

Box  ELDER  Co. — Empire  mine,  wulfenite! 

UTAH  Co. — Ammonia  alum. 

In  the  Wahsatch  and  Oquirrh  mountains  there  are  extensive  mines, 
especially  of  ores  of  lead  rich  in  silver.  At  the  Emma  mine  occur 
galenite,  cervantite,  cerussite,  wulfenite,  azurite,  malachite,  calamine, 
anglesite,  linarite,  sphalerite,  pyrite,  argentite,  stephanite,  etc.  At 
the  Lucky  Boy  mine,  Butterfield  Canon,  orpiment,  realgar. 

One  hundred  and  twenty  miles  southwest  of  Salt  Lake  City,  topaz 
has  been  found  in  colorless  crystals.  At  a  silver  mine,  fibrous  se« 
piolite. 

NEVADA. 

CARSON  VALLEY. —Chrysolite. 

CHURCHILL  Co. — Near  Ragtown,  gay-lussite,  trona,  common  salt. 

COMSTOCK  LODE. — Gold,  native  •silver,  argentite,  stephanite,  polyba, 
site,  pyrargyrite,  proustite,  tetrahedrite,  cerargyrite,  pyrite,  chalcopy 
rite,  galenite,  blende,  pyromorphite,  allemontite,  arsenolite,  quartz, 
calcite,  gypsum,  cerussite,  cuprite,  wulfenite,  amethyst,  kiistelite. 

ELKO  Co. — Emma  Mine,  chrysocolla. 

ESMERALDA  Co. — Alum,  12  m.  north  of  Silver  Creek ;  at  Aurora, 
fluorite,  stibnite  ;  near  Mono  Lake,  native  copper  and  cuprite,  obsi- 
dian;  Thiel  Salt  Marsh,  ulexite,  borax,  common  salt,  thenardite ; 
Columbus  district,  ulexite,  thenardite,  sulphur  ;  Walker  Lake,  gyp- 
sum, hematite  ;  Silver  Peak,  salt,  saltpetre,  sulphur,  silver  ores. 

HUMBOLDT  DISTRICT. — Sheba  mine,  native  silver,  jamesonite,  stib- 
nite, tetrahedrite,  proustite,  blende,  cerussite,  calcite,  bournonite,  py- 
rite, galenite,  malachite,  xanthocone  (?),  cuprite. 

LANDER  Co. — Austin,  polybasite,  chalcopyrite,  azurite. 

LINCOLN  Co. — Rock  salt,  cerargyrite. 

MAMMOTH  DISTRICT. — Ortkoclass,  turquoise,  Mbnerite,  scheelite. 

NYE  Co.— Anglesite,   stetefeldite,   azurite,   cerussite,  silver 
cerargyrite. 


368  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

REESE  RIVEK  DISTRICT. — Native  silver,  proustite,  pyrargyritc, 
Btephanite,  blende,  polybasite,  rhodochrosite,  embolite,  tetrahedrite ! 
cerargyrite,  embolite. 

SAN  ANTONIA — Belinont  mine,  stetefeldtite. 

SIX-MILE  CANON. — Selenite. 

ORMSBY  Co. — W.  of  Carson,  epidote. 

STOREY  Co. — Alum,  natrolite,  scolecite. 

WHITE  PINE  Co. — Eberhardt  mine,  cerargyrite  ;  Paymaster  mine 
freieslebenite. 

ARIZONA 

To  the  south,  south  of  Tucson,  near  the  Mexican  boundary,  the  re- 
gion about  Tubac  Arivaca,  the  Santa  Rita  and  the  Patagonia  Mts., 
noted  for  silver  mines,  the  ore  in  part  argentiferous  galenite  ;  about 
Tucson,  copper  ores  ;  a  little  to  the  north,  the  Heint/elmann  mine, 
Stromeyerite,  chalcocite,  tetrahedrite,  native  silver,  atacamite  ;  on 
and  near  the  Colorado  River,  in  Yuma  County,  the  Castle  Dome,  Eu- 
reka and  other  mines,  of  gold,  silver,  and  copper,  argentiferous  gale- 
nite the  prominent  silver  ore.  In  the  Penal  range,  gold  ;  on  the  San 
Francisco  River,  native  copper,  covellite,  chalcopyrite,  malachite,  azu- 
rite  ;  at  Bill  Williams  Fork,  malachite,  chrysocolla,  atacamite,  bro- 
chantite  ;  Montgomery  mine,  Harsayampa  district,  tetradymite. 

North  of  the  Qila,  just  west  of  the  boundary  of  New  Mexico,  chalco- 
cite, cuprite,  malachite. 


OREGON  AND   WASHINGTON. 

Gold  is  obtained  from  beach  washings  on  the  southern  coast  ;  quartz 
mines  and  placer  mines  in  the  Josephine  district ;  also  on  the  Powder, 
Burnt,  and  John  Day's  rivers,  and  other  places  in  Eastern  Oregon  ; 
platinum,  iridosmine,  laurite,  on  the  Rogue  River,  at  Port  Orford, 
and  Cape  Blanco.  In  Curry  Co. ,  priceite. 

At  Seattle,  Washington  T. — Scheelite,  tourmaline  ;  at  Fidalgo, 
realgar. 

IDAHO. 

In  the  Owyhee,  Boise,  and  Flint  districts,  gold,  also  extensive  silver 
mines  ;  Poor  Man's  Lode,  cerargyrite !  proustite,  pyrargyrite  !  -native 
silver,  gold,  pyromorphite,  quartz,  malachite,  stephanite  ;  polybasite  ; 
on  Jordan  Creek,  stream  tin  ;  Rising  Star  mine,  stephanite,  argentitet 
pyrargyrite  ;  Charity  mine,  Warren's,  scheelite,  gold. 


MONTANA. 

Many  mines  of  gold,  etc.,  west  of  the  Missouri  River.  HIGHLAND 
DISTRICT. — Tetradymite.  SILVER  STAR  DIST. — Psittacinite. 

In  the  Yellowstone  Park,  in  Montana  and  Wyoming  Territories.— 
Geyserite,  amethyst!  chalcedony,  quartz  crystals,  quartz  on  calcite, 
etc. 


CATALOGUE    OF    AMERICAN   LOCALITIES    OF   MINERALS. 

% 

COLORADO. 

The  principal  gold  mines  of  Colorado  are  in  Boulder,  Gil  pin,  Clear 
Creek,  and  Jefferson  Counties,  on  a  line  of  country  a  few  miles  W.  of 
Denver,  extending  from  Long's  Peak  to  Pike's  Peak.  A  large  portion 
of  the  gold  is  associated  with  veins  of  pyrite  and  chalcopyrite  ;  silver 
and  lead  mines  are  at  and  near  Georgetown,  Clear  Creek  County,  and 
to  the  westward  in  Summit  County,  on  Snake  and  Swan  rivers. 

At  the  GEORGETOWN  mines  are  found  : — native  silver,  pyrargyrite, 
argentite,  tetrahedrite,  pyromorphite,  galenite,  sphalerite,  azurite, 
aragonite,  barite,  fluorite,  mica. 

TRAIL  CREEK. — Garnet,  epidote,  hornblende,  chlorite  ;  at  the  Free- 
land  Lode,  tetrahedrite,  tennantite,  anglesite,  caledonite,  cerussite, 
tenorite,  siderite,  azurite,  minium  ;  at  the  Champion  Lode,  tenorite, 
azurite,  chrysocolla,  malachite  ;  at  the  Gold  Belt  Lode,  vivianite ;  at 
the  Kelly  Lode,  tenorite  ;  at  the  Coyote  Lode,  malachite,  cyano- 
trichite. 

Near  BLACK  HAWK.— At  Willis  Gulch,  enargite,  fluorite,  pyrite  ;  at 
the  Gilpin  County  Lode,  cerargyrite  ;  on  Gregory  Hill,  feldspar  ; 
North  Clear  Creek,  lievrite. — Galenite  ! 

BEAR  CREEK.  — Fluorite,  beryl  ;  near  the  Malachite  Lode,  malachite, 
cuprite,  vesuvianite,  topazolite  ;  Liberty  Lode,  chalcocite. 

SNAKE  RIVER. —Penn  District,  embolite  ;  at  several  lodes,  pyrar- 
gyrite, native  silver,  azurite. 

RUSSELL  DISTRICT. — Delaware  Lode,  cMlcopyrite,  crystallized  gal- 
enite.— Epidote,  pyrite. 

VIRGINIA  CANON. — Epidote,  fluorite  ;  at  the  Crystal  Lode,  native 
silver,  spinel. 

SUGAR  LOAF  DISTRICT. —Chalcocite,  pyrrhotite,  garnet  (mangane- 
sian). 

CENTRAL  CITY. — Garnet,  tenorite ;  at  Leavitt  Lode,  molybdenite  ; 
on  Gunnell  Hill,  magnetite  ;  at  the  Pleasantview  mine,  cerussite. 

GOLDEN  CITY. — Aragonite ;  on  Table  Mountain,  leucite  in  amygda- 
loid. 

BERGEN'S  RANCHE. — Garnet,  actinolite,  calcite. 

BOULDER  Co. — Red  Cloud  Mine  :  Native  tellurium,  altaite,  hessite 
(petzite),  sylvanite,  calaverite,  schirmerite.  Keystone  Mine  :  Colora- 
doite,  magnolite,  ferotellurite,  tellurite,  roscoelite  ?  also  part  of  these 
at  Smuggler  mine  and  Mountain  Lion  mine.  Grand  View  mine  :  syl- 
vanite, etc. 

LAKE  CITY,  at  the  Hotchkiss  Lode. — Petzite,  calaverite  (?),  etc. 

LAKE  Co.,  Golden  Queen  mine. — Scheelite,  gold. 

PIKE'S  PEAK,  on  Elk  Creek. — Amazon-stone!  !  smoky  quartz!  aven- 
turine  feldspar,  amethyst,  albite,  fluorite,  hematite,  anhydrite  (rare), 
columbite. 

SAN  JUAN  DISTRICT. — Gold,  sphalerite,  pyrite,  galenite,  chalcocite, 
covellite,  chalcopyrite. 

CANADA  EAST. 

ABERCROMBIE. — Labrador!  te. 

AUBERT. — Gold,  iridosmine,  platinum. 

BAIE  ST.  PA.Tji*.~-Menaccanite  f  apatite,  allanite,  rutile. 


370  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

BOLTON. — Chromite,  magnesite,  serpentine,  picrolite,  steatite,  bitter 
spar,  wad,  rutile. 

BOUCHEBVILLE. — Auyite  in  trap. 

BROME. — Magnetite,  chal  copy  rite,  spJiene,  menaccanite,  phyllite, 
sodalite,  cancrinite,  galenite,  chloritoid,  rutile. 

BROUGHTON. — Serpentine,  steatite. 

CHAMBLY. — Analcite,  cliabazite  and  calcite  in  trachyte,  menaccanite. 

CHATEAU  RICHER. — Labrador -ite,  hypersthene,  andesite. 

DAILLEBOUT. — Blue  spinel  with  clintonite. 

GRENVILLE. — Wollastonite,  sphene,  muscotite,  vesuvianite,  calcite, 
pyroxene,  serpentine,  steatite  (rensselaerite),  chondrodite,  garnet  (cin- 
namon-stone), zircon,  graphite,  scapolite. 

FITZROY.  —  G  raphite. 

HAM. — Chromite  in  serpentine,  diallage,  antimony!  senarmontite  ! 
kermesite,  valentinite,  stibnite. 

HUNTERSTOWN. — Scapolite,  sphene,  vesuvianite,  garnet,  brown  tour- 
maline ! 

INVERNESS. — Bornite,  chalcocite,  pyrite. 

LAKE  ST.  FRANCIS. — Andalusite  in  mica  slate. 

LEEDS. — Dolomite,  chalcopyrite,  gold,  chloritoid,  chalcocite,  bornite, 
pyrite,  steatite. 

MILLE  ISLES. — Labradorite!  menaccanite,  hypersthene,  andesite, 
zircon. 

MONTREAL. — Calcite,  augite,  sphene  in  trap,  chrysolite,  natrolite, 
dawsonite. 

MORIN. — Sphene,  apatite,  labradorite. 

ORFORD. — White  garnet,  chrome  garnet,  mitterite,  serpentine. 

OTTAWA. — Pyroxene.  • 

PORTAGE  DE  FORT. — Rensselaerite. 

POTTON. — Chromite,  steatite,  serpentine,  amiantlius. 

ROUGEMONT. — Augite  in  trap. 

ST.  ARMAND.— Micaceous  iron  ore  with  quartz,  epidote. 

ST.  FRANCOIS  BEAUCE. — Gold,  platinum,  iridosmine,  menaccaiiite, 
magnetite,  serpentine,  chromite,  soapstone,  barite. 

ST.  JEROME. — Sphene,  apatite,  chondrodite,  phlogopite,  tourmalinet 
zircon,  garnet,  molybdenite,  pyrrhotite,  wollastonite,  labradorite. 

ST.  NORBERT.— Amethyst  in  greenstone. 

SHERBROOK.— At  Suffield  mine,  albite!  native  silver,  argentite, 
chalcopyrite,  blende. 

SOUTH-CROSBY.  — Chondrodite. 

STUKELEY. — Serpentine,  verd-antique  !  schiller  spar. 

SUTTON. — Magnetite,  in  fine  crystals,  hematite,  rutilet  dolomite, 
magnesite,  chromiferous  talc,  bitter  spar,  steatite. 

UPTON. — Chalcopyrite,  malachite,  calcite. 

VAUDREUIL. — Limonite,  vivianite. 

YAMASKA. — Sphene  in  trap. 

CANADA  WEST. 

ARNPRIOR. — Calcite. 

BALSAM  LAKE. — Molybdenite,  scapolite,  quartz,  pyroxene,  pyrite. 
BATHURST. — Barite,  black  tourmaline,  perthite  (orthoclase),  peristerite 
(albite),  bytoumite,  pyroxene,  wilsonite,  scapolite,  apatite,  titanite. 


CATALOGUE   OP   AMERICAN    LOCALITIES   OF   MINERALS.         371 

BRANTFORD. — Sulphuric  acid  spring  (4 '2  parts  of  pure  sulphuric 
acid  in  1,000). 

BROCK  VILLE.  — Pyrite. 

BROME.  — Magnetite. 

BRUCE  MINES  on  Lake  Huron. — Calcitc,  dolomite,  quartz,  chalcopy 
rite,  chalcocite. 

BURGESS. — Pyroxene,  albite,  mica,  corundum,  sphene,  chalcopyrite, 
apatite,  black  spinel !  spodumene  (in  a  boulder),  serpentine,  biotite. 

BYTOWN. — Calcite,  lytomiite,  chondrodite,  spinel. 

CAPE  IPPERWASH,  Lake  Huron. — Oxalite  in  shales. 

CHAUDIERE  VALLEY. — Gold,  sphalerite,  pyrite,  pyrrhotite,  galenite. 

CLARENDON. —  Vesuvianite,  tourmaline. 

DALHOUSIE. — Hornblende,  dolomite. 

DRUMMOND.  —  Labradorite. 

ELIZABETHTOWN.— Pyrrhotite,  pyrite,  calcite,  magnetite,  talc,  phlo- 
gopite,  sidcrite,  apatite,  cacoxenite. 

ELMSLEY. — Pyroxene,  sphene,  feldspar,  tourmaline,  apatite,  biotite, 
zircon,  red  spinel,  chondrodite. 

FITZROY. — Amber,  brown  tourmaline,  in  quartz. 

GOETINEAU  RIVER,  Blasdell's  Mills.— Calcite,  apatite,  tourmaline, 
hornblende,  pyroxene. 

GRAND  CALUMET  ISLAND. — Apatite  plilogopite!  pyroxene!  horn- 
blende, sphene,  vcsuvianite  !  !  serpentine,  tremolite,  scapolite,  brown 
and  black  tourmaline!  pyrite,  loganite. 

HIGH  FALLS  OF  THE  MADAWASKA. — Pyroxene  !  hornblende. 

HULL. — Magnetite,  garnet,  graphite. 

HUNTINGTON. — Calcite  ! 

INNISKILLEN.  — Petroleum. 

KINGSTON. — Celestite. 

LAC  DES  CHATS,  Island  Portage.— Brmcn  tourmaline!  pyrite,  cal- 
cite, quartz. 

LANARK. — Raphilite  (hornblende),  serpentine,  asbestus,  perthite 
(aventurine  feldspar),  peristerite. 

LANSDOWNE.  —  Barite !  vein  27  in.  wide,  and  fine  crystals,  rens. 
selaerite,  sphalerite,  wilsonite,  labradorite. 

MADOC.— Magnetite. 

MARMORA. — Magnetite,  chalcolite,  serpentine,  garnet,  epsomite, 
specular  iron,  steatite. 

McNAB.— Hematite,  barite. 

MICHIPICOTON  ISLAND,  Lake  Superior. — Domeykite,  nicolite,  gen- 
thite,  chalcopy  rite,  native  copper,  native  silver,  chalcocite,  galenite, 
amethyst,  calcite,  stilbite,  analcite.  At  Maimanse  Bay:  Coracite, 
chalcocite,  clialcopyrite,  native  copper. 

N E WBOROUGH. —Ghon drodite,  graphite. 

P  AKENH  AM.  — Hornblende. 

PERTH. — Apatite  in  large  beds,  phlogopite. 

ST.  ADELE. — Chondrodite  in  limestone. 

ST.  IGNACE  ISLAND. — Calcite,  native  copper. 

SILVER  ID.,  Lake  Superior.— Argentite,  native  silver,  galenite,  nic- 
colite,  chalcocite,  malachite. 

SYDENHAM.— Celestite. 

TERRACE  COVE,  Lake  Superior. — Molybdenite. 

WALLACE  MINE,  Lake  Hurpn. — Hematite,  nickel  ore,  nickel  vitriol, 
tfiakopyrite. 


372  SUPPLEMENT   TO    DESCRIPTIONS    OF    SPECIES. 

NEW  BRUNSWICK. 

ALBEBT  Co. — Hopewell,  gypsum  ;  Albert  mines,  coal  (albertite) ; 
Shepody  Mountain,  alunite  in  clay,  calcite,  pyrite,  manganite,  psilo- 
melane,  pyrolusite. 

CARLETON  Co.  —  Woodstock,  chalcopyrite,  hematite,  limonite, 
wad. 

CHARLOTTE  Co. — Campobello,  at  Welchpool,  blende,  chalcopyrite, 
bornite,  galenite.  pyrite  ;  at  head  of  Harbor  de  Lute,  galenite  ;  Deer 
Island,  on  west  side,  calcite,  magnetite,  quartz  crystals  ;  Digdighash 
River  on  west  side  of  entrance,  calcite  !  (in  conglomerate),  chalcedony  ; 
at  Rolling  Dam,  graphite  ;  Grandmanan,  between  Northern  Head  and 
Dark  Harbor,  agate,  amethyst,  apophyllite,  calcite,  hematite,  heulan- 
dite,  jasper,  magnetite,  natrolite,  stilbite ;  at  Whale  Cove,  calcite! 
heulandite,  laumontite,  stilbite,  semi-opal !;  Wagaguadavic  River,  at 
entrance,  azurite,  chalcopyrite  in  veins,  malachite. 

GLOUCESTER  Co. — Tete-a-Gouche  River,  eight  miles  from  Bathurst, 
chalcopyrite  (mined),  oxide  of  manganese  !  !  formerly  mined. 

KINGS  Co.— Sussex,  near  Gloat's  mills,  on  road  to  Belleisle,  argen- 
tiferous galenite ;  one  mile  north  of  Baxter's  Inn,  specular  iron  in 
crystals,  limonite  ;  on  Capt.  McCready's  farm,  selenite  !  ! 

RESTIGOUCHE  Co. — Belledune  Point,  calcite!  serpentine,  verd-an- 
tique;  Dalhousie,  agate,  carnelian. 

ST.  JOHN  Co. — Black  River,  on  coast,  calcite,  chlorite,  chalcopyrite, 
hematite  !  Brandy  Brook,  epidote,  hornblende,  quartz  crystals  ;  Carle- 
ton,  near  Falls,  calcite ;  Chance  Harbor,  calcite  in  quartz  veins,  chlo- 
rite in  argillaceous  and  talcose  slate  ;  Little  Dipper  Harbor,  on  west 
side,  in  greenstone,  amethyst,  barite,  quartz  crystals  ;  Moosepath, 
feldspar,  hornblende,  muscovite,  black  tourmaline ;  Musquash,  on 
east  side  harbor,  copperas,  graphite,  pyrite  ;  at  Shannon's,  chrysolite, 
serpentine  ;  east  side  of  Musquash,  quartz  crystals  ! ;  Portland  at  the 
Falls,  graphite  ;  at  Fort  Howe  Hill,  calcite,  graphite  ;  Crow's  Nest, 
asbestus,  chrysolite,  magnetite,  serpentine,  steatite  ;  Lily  Lake,  white 
augite  ?  chrysolite,  graphite,  serpentine,  steatite  talc  ;  How's  Road, 
two  miles  out,  epidote  (in  syenite),  steatite  in  limestone,  tremolite ; 
Drury's  Cove,  graphite,  pyrite,  pyrallolite?  indurated  talc  ;  Quaco,  at 
Lighthouse  Point,  large  bed  oxide  of  manganese  ;  Sheldon's  Point, 
actinolite,  asbestus,  calcite,  epidote,  malachite,  specular  iron  ;  Cape 
Spenser,  asbestus,  calcite,  chlorite,  specular  iron  (in  crystals)  ;  West- 
beach,  at  east  end  on  Evans's  Farm,  chlorite,  talc,  quartz  crystals; 
half  a  mile  west,  chlorite,  chalcopyrite,  magnesite  (vein),  magnetite  ; 
Point  Wolf  and  Salmon  River,  asbestus,  chlorite,  chrysocolla,  chalco- 
pyrite, bornite,  pyrite. 

VICTORIA  Co. — Tabique  River,  agate,  carnelian,  jasper;  at  mouth, 
south  side,  galenite  ;  at  mouth  of  Wapskanegan,  gypsum,  salt  spring; 
three  miles  above,  stalactites  (abundant)  ;  Quisabis  River,  blue  phos- 
phate of  iron,  in  clay. 

WESTMORELAND  Co.— Bellevue,  pyrite  ;  Dorchester,  on  Taylor's 
Farm,  cannel  coal ;  clay  ironstone  ;  on  Ayres's  Farm,  asphaltum,  petro- 
leum spring  ;  Grandlance,  apatite,  selenite  (in  large  crystals) ;  Mem- 
ram  cook,  coal  (albertite)  ;  Shediac,  four  miles  up  Scadoue  River,  coal. 

YORK  Co.  —  Near  Fredericton,  stibnite,  jamesonite,  berthierite ; 
Pokiock  River,  stibnite,  tin  pyrites?  in  granite  (rare). 


CATALOGUE  OP  AMERICAN  LOCALITIES  OP  MINERALS.    373 

NOVA  SCOTIA. 

ANNAPOLIS  Co. — Chute's  Cove,  apophyllite,  natrolite  ;  Gates's  Moun- 
tain, anal  cite,  magnetite,  mesolile  !  natrolite,  stilbite;  Martial's  Cove, 
analcite  /  chabazite,  heulandite ;  Moose  River,  beds  of  magnetite  ; 
Nictau  River,  at  the  Falls,  bed  of  hematite ;  Paradise  River,  black 
tourmaline,  smoky  quartz  !! ;  Port  George,  faroelite,  laumontite,  me- 
solite,  stilbite  ;  east  of  Port  George,  on  coast,  apophyllite  containing 
gyrolite  ;  Peter's  Point,  west  side  of  Stonock's  Brook,  apophyllite ! 
calcite,  heulandite,  laumontite  !  (abundant),  native  copper,  stilbite  ;  St. 
Croix's  Cove,  chabazite,  heulandite. 

COLCHESTER  Co.— Five  Islands,  East  River,  'barite!  calcite,  dolo- 
mite (ankerite),  hematite,  chalcopyrite ;  Indian  Point,  malachite, 
magnetite,  red  copper,  tetrahedrite  ;  Pinnacle  Islands,  analcite,  calcite, 
chabazite  !  natrolite,  siliceous  sinter  ;  Londonderry,  on  branch  of  Great 
Village  River,  barite,  ankerite,  hematite,  Hmonite,  magnetite ;  Cook's 
Brook,  ankerite,  hematite  ;  Martin's  Brook,  hematite,  limonite ;  at 
Folly  River,  below  Falls,  ankerite,  pyrite  ;  on  high  land,  east  of  river, 
ankerite,  hematite,  limonite  ;  on  Archibald's  land,  ankerite,  barite^ 
hematite  ;  Salmon  River,  south  branch  of,  chalcopyrite,  hematite ; 
Shubenacadie  River,  anhydrite,  calcite,  barite,  hematite,  oxide  of 
manganese  ;  at  the  Canal,  pyrite  ;  Stewiacke  River,  barite  (in  lime- 
stone). 

CUMBERLAND  Co.— Cape  Chiegnecto,  barite  ;  Cape  d'Or,  analcite, 
apophyllite!!  chabazite,  faro'elite,  laumontite,  mesolite,  malachite, 
natrolite,  native  copper,  obsidian,  red  copper  (rare),  vivianite  (rare) ; 
Horse  Shoe  Cove,  east  side  of  Cape  d'Or,  analcite,  calcite,  stilbite ; 
Isle  Haute,  south  side,  analcite,  apophyllite !!  calcite,  heulandite !! 
natrolite,  mesolite,  stilbite  ! ;  Joggins,  coal,  hematite,  limonite  ;  mala- 
chite and  tetrahedrite  at  Seaman's  Brook  ;  Partridge  Island,  analcite, 
apophyllite!  (rare\  amethyst!  agate,  apatite  (rare),  calcite!!  chabazite 
(acadialite),  chalcedony,  cat's  eye  (rare),  gypsum,  hematite,  heulan- 
dite !  magnetite,  stilbite !! ;  Swan's  Creek,  west  side,  near  the  Point, 
calcite,  gypsum,  heulandite,  pyrite  ;  east  side,  at  Wasson's  Bluff  and 
vicinity,  analcite!!  apophyllite!  (rare\  calcite,  chabazite!!  (acadialite), 
gypsum,  heulandite !!  natrolite !  siliceous  sinter ;  Two  Islands,  moss 
agate,  analcite,  calcite,  chabazite,  heulandite;  McKay's  Head,  anal- 
cite, calcite,  heulandite,  siliceous  sinter! 

DIGBY  Co.  —  Briar  Island,  native  copper,  in  trap  ;  Digby  Neck, 
Sandy  Cove  and  vicinity,  agate,  amethyst,  calcite,  chabazite,  hsmatite ! 
laumontite  ( abundant  \  magnetite,  stilbite,  quartz  crystals  ;  Gulliver's 
Hole,  magnetite,  stilbite! ;  Mink  Cove,  amethyst,  chabazite!  quartz 
crystals;  Nichols  Mountain,  south  side,  amethyst,  magnetite!;  Wil- 
liams Brook,  near  source,  chabazite  (green),  heulandite,  stilbite,  quartz 
crystal. 

GUYSBORO'  Co. — Cape  Canseau,  andalusite. 

HALIFAX  Co. — Gay's  River,  galenite  in  limestone ;  southwest  of 
Halifax,  garnet,  staurolite,  tourmaline  ;  Tangier,  gold!  in  quartz 
veins  in  clay  slate,  associated  with  auriferous  pyrite,  galenite,  hema- 
tite, arsenopyrite,  and  magnetite  ;  gold  at  Country  Harbor,  Fort  Clar- 
ence, Isaac's  Harbor.  Indian  Harbor,  Laidlow's  Farm,  Lawrencetown, 
Sherbrooke,  Salmon  River,  Wine  Cove,  and  other  places. 

HANTS  Co.— Cheverie,  oxide  of  manganese  (in  limestone) ;  Petite 


3?4  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

River,  gypsum,  oxide  of  manganese  ;  Windsor,  calcite,  cryptomorpL  » 
(baronatiocalcite),  howlite,  glauber  salt.  The  last  three  minerals  are 
found  in  beds  of  gypsum. 

KINGS  Co. — Black  Rock,  centrallassite,  cerinite  ;  cyanolite  ;  a  few 
miles  east  of  Black  Rock,  prehnite  ?  stilbite ! ;  Cape  Blomidon,  on  the 
coast  between  the  cape  and  Cape  Split,  the  following  minerals  occur 
in  many  places  (some  of  the  best  localities  are  nearly  opposite  Cape 
Sharp) :  anakite !!  agate,  amethyst !  apophyttite !  calcite,  chalcedony, 
chabazite,  gmelinite  (lederite),  hematite,  heulandite!  laumontite,  mag- 
netite, malachite,  mesolite,  native  copper  (rare),  natrolite  f  psilomelane, 
stilbite!  thomsonite,  faroelite,  quartz;  North  Mountains,  amethyst, 
bloodstone  (rare),  ferruginous  quartz,  mesolite  (in  soil) ;  Long  Point, 
five  miles  west  of  Black  Rock,  heulandite,  laumontite!!  stilbite!!; 
Mordeu,  apophyttite,  mordenite ;  Scott's  Bay,  agate,  amethyst,  chalce- 
dony, mesolite,  natrolite  ;  Woodworth's  Cove,  a  f  Av  miles  west  of 
Scott's  Bay,  agate  !  chalcedony !  jasper. 

LUNENBERG  Co. — Chester,  Gold  River,  gold  in  quartz,  pyrite,  mis- 
pickel ;  Cape  la  Have,  pyrite  ;  The  "  Ovens,"  gold,  pyrite,  arseno- 
pyrite  ;  Petite  River,  gold  in  slate. 

PICTOU  Co. — Pictou,  jet,  oxide  of  manganese,  limonite  ;  at  Roder*s 
Hill,  six  miles  west  of  Pictou,  barite  ;  on  Carribou  River,  gray  copper 
and  malachite  in  lignite  ;  at  Albion  mines,  coal,  limonite  ;  East  River, 
limonite. 

QUEEN'S  Co. — Westfield.  gold  in  quartz,  pyrite,  arsenopyrite  ;  Five 
Rivers,  near  Big  Fall  gold  in  quartz,  pyrite,  arsenopyrite,  limonite. 

RICHMOND  Co. — West  of  Plaister  Cove,  barite  and  calcite  in  sand- 
stone ;  nearer  the  Cove,  calcite,  fluorite  (blue),  sideiite. 

SHELBURNE  Co. — Shelburne  near  mouth  of  harbor,  garnets  (in 
gneiss) ;  near  the  town,  rose  quartz  ;  at  Jordan  and  Sable  River,  stau- 
rolite  (abundant),  schiller  spar. 

SYDNEY  Co. — Hills  east  of  Lochaber  Lake,  pyrite,  chalcopyrite,  side- 
rite,  hematite  ;  Moiristown,  epidote  in  trap,  gypsum. 

YARMOUTH  Co. — Cream  Pot,  above  Cranberry  Hill,  gold  in  quartz, 
pyrite  ;  Cat  Rock,  Fouchu  Point,  asbestus,  calcite. 


NEWFOUNDLAND. 

ANTONY'S  ISLAND.—  Pyrite. 

CATALINA  HARBOR. — On  the  shore,  pyrite  ! 

CHALKY  HILL. — Feldspar. 

COPPER  ISLAND,  one  of  the  Wadham  group. — Chalcopyrite. 

CONCEPTION  BAY. — On  the  shore  south  of  Brigus,  bornite  and  gray 
copper  in  trap. 

BAY  OF  ISLANDS. — Southern  shore,  pyrite  in  slate. 

LAWN. — Galenite,  cerargyrite,  proustite,  argentite. 

PLACENTIA  BAY. — At  La  Manche.  two  miles  eastward  of  Little 
Southern  Harbor,  galenite  ! ;  on  the  opposite  side  of  the  isthmus  from 
Placentia  Bay,  barite  in  a  large  vein,  occasionally  accompanied  by 
chalcopyrite. 

SHOAL  BAY. — South  of  St.  John's,  chalcopyrite. 

TRINITY  BAY. — Western  extremity,  barite. 

HARBOR  GREAT  ST.  LAWRENCE.— West  side,  fluorite,  galenite. 


FOREIGN   MINING   REGIONS.  375 

BRITISH  COLUMBIA. 

CARIBOO  DISTRICT. — Native  gold,  galena. 

ON  FRAZER  RIVER. — Gold,  argentiferous  tetrahedrite,  cerargyrite, 
cinnabar. 

OMINICA  DISTRICT. — Native  gold,  argentiferous  galenite,  native 
silver,  silver-amalgam. 

HOWE'S  SOUND. — Bornite,  molybdenite,  mica. 

TEXADA  ID. — Magnetite. 


II.    BRIEF  NOTICE  OF  FOREIGN  MINING 
REGIONS. 

THE  geographical  positions  of  the  different  mining  regions  are  learned 
with  difficulty  from  the  scattered  notices  in  the  course  of  a  minera- 
logical  treatise.  A  general  review  of  the  more  important  is  therefore 
here  given,  to  be  used  in  connection  with  a  good  map. 

A  course  across  Europe,  from  southeast  to  northwest,  passes  over  a 
large  part  of  the  mining  regions,  and  it  will  be  found  most  convenient 
to  the  memory  to  mention  them  in  this  order,  commencing  with  the 
borders  of  Turkey. 

1.  The  mines  of  the  Bannat  in  Southern  Hungary,  near  the  borders 
of  Turkey  (about  latitude  45°),  situated  principally  at  Orawitza,  Sasz- 
ka,  Dognaszka,  and  Moldawa  :  argentiferous  copper  ores,  chalcocite, 
malachite,  copper  pyrites,  cuprite,  galenite,  ores  of  zinc,  cobalt,  native 
gold  ;  yielding  silver,  gold,  copper,  and  lead  ;  rock :  syenyte,  and  gran- 
ular limestone. 

2.  The  mines  of  Western  Transylvania,  about  latitude  46°,  situated 
between  the  rivers  Maros  and  Aranyos,  at  Nagyag,  Offenbanya,  Sa- 
lathna,  and  Vorospatak  :  native  gold,  telluric   gold,  telluric  silver, 
white  tellurium,  with  galenite,  blende,  orpiment,  realgar,  stibnite,  tet- 
rahedrite, rhodochrosite  or  carbonate  of  manganese,  manganblende  ; 
especially  valuable  in  gold  and  silver. 

3.  In  the  mountain  range,  bounding  Transylvania  on  the  north, 
about  latitude  47°  40',  at  Nagybanya,  Felsobanya,  and  Kapnik  :  na- 
tive gold,  red  silver,  argentiferous  tetrahedrite,  chalcopyrite  or  pyri- 
tous  copper,  blende,  realgar,  stibnite  or  gray  antimony  ;   rock :  por- 
phyry. 

4.  In  the  Konigsberg  Mountains,  Northern  Hungary,  about  latitude 
48°  45',  at  Schemnitz  and  Kremnitz  :  argentiferous  galenite,  and  chal- 
copyrite, native  gold,  red  silver  ore,  stibnite,  some  cobalt  ores  and  bis- 
muth, arsenopyrite  or  mispickel  ;  particularly  valuable  for  gold,  sil- 
ver and  antimony  ;  rock  :  diorite  and  porphyry. 

5.  To  the  east  of  the  Konigsberg  Mountains,  at  Schmolnitz  and  Retz- 
banya  :  chalcopyrite,  tetrahedrite,  blende,  stibnite  ;  particularly  valu- 
able for  copper  ;  rock  :  clay  slate. 

6.  Illyria,  west  of  Hungary,  at  Bleiberg  and  Raibel  (in  Carinthia) : 
argentiferous  galenite,  calamine,  with  some  chalcopyrite  and  other 
ores,  affording  silver  and  zinc  abundantly  ;  rock :  mountain  limestone. 
— Also  at  Idria,  native  mercury  and  cinnabar,  in  argillaceous  schist, 


376  SUPPLEMENT   TO   DESCRIPTIONS   OF   SPECIES. 

7.  In   Western   Styria,    at   Schladming :    arsenical  nickel,    copper 
nickel,  native  arsenic,  arsenical  iron,  largely  worked  for  nickel ;  rock  : 
argillaceous  slate.     Illyria  and  Styria  are  noted  also  for  their  iron  ores, 
especially  siderite  or  spathic  iron. 

8.  In  the  Tyrol,  at  Zell :  argentiferous  copper  and  iron  ores,  aurife- 
rous pyrite,  native  gold  ;  rock :  argillaceous  slate. 

9.  In  the  Erzgebirge  separating  Bohemia  from  Saxony,  and  consist- 
ing principally  of  gneiss  : 

A.  Bohemian  or  southern  slope,  at  Joachimsthal,  Mies,  Schlacken- 
wald,  Zinnwald,  Bleistadt,  Przibram,  Katherinenberg  :  tin  ores,  ar- 
gentiferous galenite  (worked  principally  for  silver),  arsenical  cobalt 
ores,  copper  nickel ;  affording  tin,  silver,  cobalt,  nickel  and  arsenic. 

B.  Saxon  or  northern  slope,  at  Altenberg,  Geyer,  Marienberg,  Anna- 
berg,  Schneeberg,  Ehrenfriedersdorf,  Johanngeorgenstadt,  Freiberg  : 
argentiferous  galenite  (worked  only  for  silver),  tin  ore,  various  cobalt 
and  nickel  ores,  vitreous  and  pyritous  copper  ;  affording  silver,  tin, 
cobalt,  nickel,  bismuth,  and  copper. 

10.  In  Silesia,  in  the'Riesengebirge.  an  eastern  extension  of  the  Erz- 
gebirge, at  Kupferberg,  Jauer,  Reichenstein :  ores  of  copper,  cobalt, 
affording  copper,  cobalt,  arsenic  and  sulphur. 

11.  In  Silesia,  in  the  low  country  east  of  the  Riesengebirge,  near 
the  boundary  of  Poland,  at  Tarnowitz  :  calamine,  smithsonite,  blende, 
argentiferous  galenite  ;  affording  zinc,  silver  and  lead  ;  rock :  moun- 
tain limestone. 

12.  Northwest  of  Saxony,  near  latitude  51°  30',  at  Eisleben,  Gerlstadt. 
Sangerhausen,  and  Mansfeld  :   tetrahedrite,  somewhat  argentiferous, 
bornite  or  variegated  copper  ore,  affording  copper  ;  rock :  a  marly  bi- 
tuminous schist  (kupferschiefer)  more  recent  than  the  Carboniferous 
strata. 

13.  In  the  Harzgebirge  (Hartz  Mountains),  north  of  west  from  Eis- 
leben, about  latitude  51°  50',  at  Clausthal,  Zellerfeld,  Lauthenthal, 
Wildemann,  Grund,  Andreasberg,  Goslar,  Lauterberg  :   chalcocite  or 
vitreous  copper,  tetrahedrite,  chalcopyrite,  cobalt  ores,  copper  nickel, 
ruby  silver  ore,  argentiferous  galenite.  blende,  antimony  ores  ;  afford- 
ing silver,  lead,  copper,  and  some  gold. 

14.  In  Hesse-Cassel,  to  the  southwest  of  the  Hartz,  at  Riechelsdorf  : 
arsenical  cobalt,  arsenical  nickel,  nickel  ochre,  native  bismuth,  bis- 
muthinite,  galenite,  affording  cobalt ;  rock :  red  sandstone.      Also  at 
Bieber,  cobalt  ores  in  mica  slate. 

15.  In  the  Bavarian  or  Upper  Rhine  (Palatinate),  near  latitude  49° 
45',  at  Landsberg  near  Moschel,  Wolf  stein,  and  Mprsfeld  :  cinnabar, 
native  mercury,  amalgam,  horn  quicksilver,  pyrite,  some  tetrahedrite, 
and  chalcopyrite  ;  rocks  :  coal  formation. 

16.  Province  of  the  Lower  Rhine,  at  Altenberg,  near  Aix  la  Chapelle 
(or  Aachen) :   calamine,  smithsonite,    galenite,  affording  zinc ;   rock : 
limestone.    The  same  just  south  in  Netherlands,  at  Limburg,  and  also 
to  the  west  at  Vedrin,  near  Namur. 

17.  There   are  also  copper  mines  at   Saalfeld,  west  of  Saxony,  in 
Saxon-Meiningen,  in  Southern  Westphalia  near  Siegen,  in  Nassau  at 
Dillenberg,  and  elsewhere. 

18.  In  Switzerland,  at  Canton  du  Valais  :  argentiferous  galenite,  and 
valuable  nickel  and  cobalt  ores. 

19.  The  range  of  the  Vosges  parallel  with  the  Rhine,  about  St. 


FOREIGN   MINING   REGIONS.  377 

Marie  aux-Mines :  argentiferous  galenite  (affording  1-1000  of  silver), 
with  pyromorphites,  tetrahedrite,  antimonial  sulphuret  of  silver,  na- 
tive silver,  arsenical  cobalt,  native  arsenic,  and  pyrite,  occasionally 
auriferous  ;  affording  silver  and  lead  ;  rocks :  argillaceous  schist,  sye- 
nyte,  and  porphyry. 

20.  In  France  there  are  also  the  mining  districts  of  the  Alps,  Au- 
vergne  or  the  Plateau  of  Central  France,  Brittany,  and  the  Pyrenees, 
but  none  are  very  productive,  except  in  iron  ores.     Brittany  resembles 
Cornwall,  and  formerly  yielded  some  tin  and  copper.     The  valley  of 
Oisans  in  the  Alps,  at  Allemont,  contains  argentiferous  galenite,  arseni- 
cal cobalt  and  nickel,  gray  copper,  native  mercury,  and  other  ores,  in 
talcose,  micaceous  and  syenytic  schists,  but  they  are  not  now  explored. 
The  region  of  Central  France  is  worked  at  this  time  only  at  Pont- 
Gibaud,  in  the  department  of  Puy-de-Dome,  and  at  Vialas  and  Ville- 
fort  in  the  Gard.     The  former  is  a  region  of  schistose  and  granite 
rocks,  intersected  by  porphyry,  affording  some  copper,  antimony,  lead, 
and  silver  ;  the  latter  of  gneiss,  affording  lead  and  silver,  from  argen- 
tiferous galena.     The  French  Pyrenees  are  worked  at  the  present  time 
only  for  iron. 

21.  In  England  there  are  two  great  metalliferous  districts  : 

A.  On  the  southwest,  in  Cornwall,  and  the  adjoining  county  of  De- 
vonshire :  pyritous   copper  and  various  other  copper  ores,  tin  ores, 
galenite,  with  some  bismuth,  cobalt,  nickel  and  antimony  ores  ;  afford- 
ing principally  copper,  tin,  and  lead  ;  rocks :  granite,  gneiss,  micaceous 
and  argillaceous  schist,  elvanyte. 

B.  On  the  north,  in  Cumberland,  the  adjoining  parts  of  Durham, 
with  Yorkshiie  and  Derbyshire,  just  south  :  galenite,  and  other  lead 
ores,  blende,  copper  ores,  calamine  and  smithsonite  (the  zinc  ores  es- 
pecially at  Alstonmoor  in  Cumberland,  and  Castleton  and  Matlock,  in 
Derbyshire),  affording  some  zinc,  and  three-fifths  of  the  lead  of  Great 
Britain,  and  some  copper  ;  rock:  Carboniferous  limestone. 

C.  There  is  also  a  vein  of  calamine,  blende,  and  galenite,  in  the 
same  limestone  at  Holywell,  in  Flintshire,  on  the  north  of  Wales  ; 
another  of  calamine  at  Mendip  Hills,  in  Southern  England,  south  of 
the  Bristol  Channel,  in  Somersetshire,  occurring  in  magnesian  lime- 
stone ;  mines  of  copper  on  the  Isle  of  Anglesey,  in  North  Wales,  in 
Westmoreland  and  the  adjacent  parts  of  Cumberland  and  Lancashire, 
in  the  southwest  of  Scotland,  the  Isle  of  Man,  and  at  Ecton  in  Stafford- 
shire, &c. 

22.  In  Spain  there  are  mines — 

A.  On  the  south,  in  the  mountains  near  the  Mediterranean  coast, 
in  New  Grenada,  and  east  to  Carthagena,  in  Murcia ;   also  in  New 
Grenada,  in  the  Sierra  Nevada,  or  the  mountains  of  Alpujarras,  the 
Sierra  Almagrera,  the  Sierra  de  Gador,  just  back  of  Almeria,  and  at 
Almazarron  near  Carthagena  :  galenite,  which  is  argentiferous  at  the 
Sierra  Almagrera  and  at  Almazarron,    affording  full  1  per  cent,  of 
silver  ;  rock :  limestone,  associated  with  schist  and  crystalline  rocks. 

B.  The  vicinity  of  the  range  of  mountains  running  westward  from 
Alcaraz  (to  the  district  of  La  Mancha),  to  Portugal.     1.  On  the  south, 
near  the  centre  of  the  province  of  Jaen,  at  Linares,  latitude  38°  5', 
longitude  3°  40':  galenite,  cerussite,  cuprite,  malachite,  in  granite  and 
schists ;   affording  lead  and  copper.     2.  In  La  Mancha,  at  Alcaraz, 
northeast  of  Linares,  latitude  38°  45' :  calamine  affording  abundantly 


378  SUPPLEMENT   TO   DESCRIPTIONS  OF   SPECIES. 

zinc.  3.  In  the  west  extremity  of  La  Mancha,  near  latitude  88°  38', 
at  Almaden  :  cinnabar,  native  mercury,  pyrite,  in  clay  slate.  4.  South- 
west of  Almaden,  in  Southern  Estremadura,  and  Northwestern  Seville : 
tetrahedrite  ;  at  Guadalcanal,  Cazalla,  Rio  Tinto  :  chalcanthite  or  cop- 
per vitriol,  malachite,  with  some  red  silver  ore,  and  native  silver,  in 
schists  or  limestones. 

There  are  also  mines  of  lead  and  copper  at  Falsete  in  Catalonia  ;  in 
Galicia,  a  little  tin  ore  ;  in  the  Asturias  at  Cabrales,  copper  ores. 

23.  In  Sweden  :  - 1.  At  Fahlun,  in  Dalecarlia  :  chalcopyrite,  bornite  ; 
rock,  syenyte  and  schists.     At  Finbo  and  Broddbo  :  tantalum  ores,  tin 
ore.     At  Sala  :  argentiferous  galeuite,  affording  lead  and  silver  ;  rock, 
crystalline  limestone.     At  Vena  (or  Wehna)  and  at  Tunaberg  :  arseni- 
cal cobalt,  erythrite  ;  rock,  mica  slate  and  gneiss.    At  Dannemora  and 
elsewhere  :  magnetic  iron  ore  or  magnetite. 

24.  In  Norway,  at  Kongsberg  :  argentite  or  vitreous  silver,  native 
silver,  horn  silver,  native  gold,  galenite,  native  arsenic,  blende  ;  rock, 
mica  slate.     At  Modum  and  Skutterud  :    cobalt  ores,  native  silver ; 
rock,  mica  slate.     At  Arendal,  magnetic  iron  ore. 

25.  In  Russia: — In  the    Urals   (mostly  on    the   Asiatic   side),    at 
Ekatherinenberg,  Beresof,   Nischne  Tagilsk,  etc.  :  native  gold,  plati- 
num,   iridium,   native    copper,    cuprite,    malachite.      2.    The   Altai 
(Southern  Siberia),  at  Kolyvan  and  Zmeof  :  native  gold,  native  silver, 
argentiferous  galena,  cerussite,  native  copper,  oxides  of  copper,  mala- 
chite, chalcopyrite;  rocks,  metamorphic  ^eds  and  porphyry.    3.  In  the 
Daouria  Mountains,  east  of  Lake  Baikal,  at  Nertchinsk  :  argentifer- 
ous galenite,  cerussite,  mimetite,  gray  antimony,  arsenopyrite,  cala- 
mine,  cinnabar  ;  rocks,  compact  limestone  and  schists. 

26.  In  Australia :— In  Southern  Queensland,  and  the  northern  part 
of  New  South  Wales,  or  the  New  England  district  :  tin  ore  or  cassi- 
terite  abundant,  with  also  native  gold.     In  New  South  Wales,  along 
the  Blue  Mountains  and  the  continuation  of  the  range  parallel  with 
the  coast  north  and  south,  in  the  Bathurst,  Mudgee,  Lachlan  and  other 
districts :  native  gold,  chalcopyrite,  some  cinnabar.     In  Victoria :  na- 
tive gold.     In  South  Australia,  especially  at  the  Burra,  Wallaroo,  and 
Moonta  mines  :  copper  ores. 

Other  foreign  mining  regions  are  the  copper  mines  of  Cuba,  and 
South  America  ;  the  silver  mines  of  Chili,  Bolivia,  Peru  in  South 
America,  and  of  Mexico  ;  the  gold  mines  of  South  America,  especially 
those  of  Brazil,  South  Africa,  and  of  the  Philippines,  Borneo,  New 
Guinea,  New  Caledonia,  and  New  Zealand  in  Australasia  ;  the  quick- 
silver mines  of  Huanca  Velica,  Peru,  and  those  of  China  ;  the  tin 
mines  of  Malacca  (principally  on  the  island  of  Junk-Ceylon),  and  of 
the  island  of  Banco  between  Borneo  and  Sumatra  ;  of  zinc,  in  China ; 
of  platinum,  in  Brazil,  Colombia,  St.  Domingo,  and  Borneo ;  of  palla- 
dium, in  Brazil ;  of  arsenic  in  Khoordistan,  Turkey  in  Asia,  and  also  in 
China ;  of  nickel,  in  New  Caledonia. 


DETERMINATION  OP  MINERALS.  379 


IV.  DETERMINATION  OF  MINERALS. 

Itf  the  determination  of  minerals,  no  one  order  in  the 
succession  in  which  characters  should  be  examined  answers 
for  all  minerals,  or  even  for  all  of  the  same  section  of  species. 

A.  For  species  having  a  metallic  lustre  : 

Color  will  be  first  noted  ;  and  then  streak — that  is,  the 
color  of  the  mineral  on  a  surface  scratched  or  abraded  by  a 
fine  file,  or  when  very  finely  powdered,  and  the  lustre  of  the 
powder  or  abraded  surface,  whether  metallic  like  the  min- 
eral or  unmetallic.  Hardness  should  be  ascertained  when 
obtaining  the  streak. 

Bloivpipe  and  chemical  characters  are  of  the  highest  value, 
giving  generally  the  most  certain  results. 

Specific  gravity  is  especially  distinctive  with  species  hav- 
ing a  metallic  lustre,  since  the  differences  in  density  among 
such  species  are  usually  large.* 

Crystalline  form  and  cleavage  are  of  first  importance, 
whenever  the  specimen  allows  of  their  determination. 

B.  For  species  without  metallic  lustre  : 

Streak  is  sometimes  of  importance,  especially  among  spe- 
cies in  which  it  is  highly  colored. 

Color  is  generally  of  little  value  owing  to  the  variations 
that  frequently  come  in  through  impurities. 

Lustre  is  one  of  the  first  characters  the  eye  will  observe, 
but  its  variation  under  most  species  is  wide,  and  often  it 
is  of  little  value.  State  of  aggregation  and  fracture  for  the 
most  part  serve  to  distinguish  only  varieties. 

Hardness  is^lso  often  a  varying  character,  the  range 
under  some  species  being  from  1  to  6  in  the  scale  of  hard- 
ness ;  and  still  its  indications  are  generally  important. 

Crystalline  form  and  cleavage  are  always  important  when 
observable. 

*  In  using  the  spiral  balance  of  Jolly  (page  65),  the  spiral  spring  is  put  at  any  de- 
sired height  by  means  of  the  sliding  rod  C.  The  stand  B  is  raised  so  that  the  lower 
pan,  rf,  shall  be  in  the  water,  while  the  other,  c,  is  above  it.  The  position  of  the  in- 
dex, or  signal,  m,  is  then  noted,  by  sighting  across  it  and  observing  that  the  index 
and  the  image  of  it  in  the  mirror  are  m  the  same  horizontal  line  ;  let  *>  stand  for  it. 
Next  put  the  fragment  of  the  mineral  in  c,  and  drop  the  si  and  B  until  the  lower  pan 
hange  free  in  the  water,  and  note  the  position  of  7/1,  which  we  may  represent  by  t ; 
t-s  will  equal  the  weight  in  the  air.  Now  place  the  fragment  in  the  lower  pan.  and 
after  adjusting  again  the  stand  B,  the  position  of  m  is  noted  as  before ;  call  it  u. 
Then  t—u  =  loss  of  weight  in  water.  From  these  values  the  specific  gravity  is  at  one* 
obtained. 


380  DETERMINATION   OP   MINERALS. 

Taste  is  of  limited  value,  as  few  minerals  are  sufficiently 
soluble  ;  but  among  soluble  minerals  it  is  easily  observed, 
and  often  decisive. 

Action  of  acids,  cold  or  hot,  in  trials  as  to  effervescence, 
solubility,  gelatinizing  or  not,  and  in  making  solutions  for 
examination  with  other  reagents,  is  a  very  important  means 
of  distinguishing  species. 

Blowpipe  reactions  are  easily  obtained,  and  of  the  high- 
est value. 

Specific  gravity  is  an  important  reliance. 

Refraction  and  polarization  afford  valuable  criteria  for 
distinguishing  species,  and  in  a  few  cases  no  other  means 
are  so  reliable  short  of  chemical  analysis. 

The  following  hints  may  be  of  service  to  the  beginner  in 
the  science,  by  enabling  him  to  overcome  a  difficulty  in  the 
outset,  arising  from  the  various  forms  and  appearance  of  the 
minerals  quartz  and  limestone.  Quartz  occurs  of  nearly 
every  color,  and  of  various  degrees  of  glassy  lustre  to  a  dull 
stone  without  the  slightest  glistening.  The  common  gray- 
ish cobble-stones  of  the  fields  are  usually  quartz,  and  others 
are  dull  red  and  brown  ;  from  these  there  are  gradual  transi- 
tions to  the  pellucid  quartz  crystal  that  looks  like  the  best 
of  glass.  Sandstones  and  freestones  are  often  wholly  quartz, 
and  the  seashore  sands  are  mostly  of  the  same  material.  It 
is  therefore  probable  that  this  "mineral  will  be  often  en- 
countered in  mineralogical  rambles.  Let  the  first  trial  ot 
specimens  obtained  be  made  with  a  file,  or  the  point  of  a 
knife,  or  some  other  means  of  trying  the  hardness  ;  if  the 
file  makes  no  impression,  there  is  reason  to  suspect  the 
mineral  to  be  quartz  ;  and  if  on  breaking  it,  no  regular 
structure  or  cleavage  plane  is  observed,  but  it  breaks  in  all 
directions  with  a  similar  surface  and  a  more  or  less  vitreous 
lustre,  the  probability  is  much  strengthened  that  this  con- 
clusion is  correct.  The  blowpipe  may  next  be  used  ;  and 
if  there  is  no  fusion  produced  by  it  in  a  careful  trial  there 
can  be  little  doubt  that  the  specimen  is  in  fact  quartz. 

Calcite  (calcium  carbonate),  including  limestone,  is  an- 
other very  common  species.  If  the  mineral  collected  is 
rather  easily  impressible  with  a  file,  it  may  be  of  this  spe- 
cies ;  if  it  effervesces  freely  when  placed  in  a  test-tube  con- 
taining dilute  hydrochloric  acid,  and  is  finally  dissolved,  the 
probability  of  its  being  carbonate  of  lime  is  increased ;  if 


DETERMINATION   OF   MINERALS.  381 

the  blowpipe  produces  no  trace  of  fusion,  but  a  brilliant 
light  from  the  fragment  before  it,  but  little  doubt  remains 
on  this  point.  Crystalline  fragments  of  calcite  break  with 
three  equal  oblique  cleavages. 

Familiarized  with  these  two  Protean  minerals  by  the 
trials  here  alluded  to,  the  student  has  already  surmounted 
the  principal  difficulties  in  the  way  of  future  progress. 
Frequently  the  young  beginner,  who  has  devoted  some 
time  to  collecting  all  the  different  colored  stones  in  his 
neighborhood,  on  presenting  them  for  names  to  some  prac- 
tised mineralogist,  is  a  little  disappointed  to  learn  that, 
with  two  or  three  exceptions,  his  large  variety  includes 
nothing  but  limestone  and  quartz.  He  is  perhaps  gratified, 
however,  at  being  told  that  he  may  call  this  specimen  yel- 
low jasper,  that  red  jasper,  another  flint,  and  another  horn- 
stone,  others  chert,  granular  quartz,  ferruginous  quartz, 
chalcedony,  prase,  smoky  quartz,  greasy  quartz,  milky 
quartz,  agate,  plasma,  hyaline  quartz,  quartz  crystal,  basa- 
nite,  radiated  quartz,  tabular  quartz,  etc.,  etc.;  and  it  is 
often  the  case,  in  this  state  of  his  knowledge,  that  he  is 
best  pleased  with  some  treatise  on  the  science  in  which 
all  these  various  stones  are  treated  with  as  much  promi- 
nence as  if  actually  distinct  species  ;  being  loth  to  receive 
the  unwelcome  truth,  that  his  whole  extensive  cabinet  con- 
tains only  one  mineral.  But  the  mineralogical  student  has 
already  made  good  progress  when  this  truth  is  freely  ad- 
mitted, and  quartz  and  limestone,  in  all  their  varieties, 
have  become  known  to  him. 

The  student  should  be  familiar  with  the  use  of  the  blow- 
pipe and  the  reactions,  as  explained  on  pages  82  and  85  ; 
and  it  would  be  still  better  if  a  fuller  treatise  on  the  subject 
had  been  carefully  studied.  He  should  be  supplied  with  the 
three  acids  in  glass-stoppered  bottles  ;  a  fourth  bottle  con- 
taining hydrochloric  acid  diluted  one-half  with  water,  for 
obtaining  effervescence  with  carbonates  ;  test  tubes  ;  and 
also  the  ordinary  blowpipe  apparatus  and  tests,  including 
platinum  wire,  platinum  forceps,  glass  tube,  "  cobalt  solu- 
tion," litmus  and  turmeric  paper,  etc. 

Also  the  following : 

A  small  file,  three-cornered  or  flat,  for  testing  hardness. 

A  knife  with  a  pointed  blade  of  good  steel,  for  trying 
hardness.  It  may  be  magnetized,  to  be  used  as  a  magnet, 
though  a  good  horseshoe  magnet  of  small  size  is  better. 


382  DETERMINATION  OF  MINERALS. 

The  series  of  crystallized  minerals,  constituting  the  seals 
of  hardness  (see  page  63).  Diamond  and  talc  are  least  es- 
sential. 

Cutting  pliers,  for  removing  chips  of  a  mineral  for  blow- 
pipe or  chemical  assay. 

A  pocket- lens. 

A  hammer  weighing  about  two  pounds,  resembling  a 

stone-cutter's  hammer,  having  a 
flat  face,  and  at  the  opposite 
end  an  edge  having  the  same 
direction  as  the  handle.  The 
handle  should  be  made  of  the 
best  hickory,  and  the  mortise  to 

receive  it  should  be  as  large  as  the  handle.  A  foot  scale 
should  be  marked  on  the  handle  of  the  hammer,  divided 
into  inches,  the  smallest  divisions  needed.  It  will  be  often 
of  use  in  getting  out  a  yard-stick,  or  a  ten-foot  pole,  for 
large  measurements.  A  similar  hammer,  having  the  upper 
part  prolonged  to  a  blunt  point,  to  be  used  like  a  pick,  is 
often  convenient. 

A  hammer  of  half  a  pound  weight,  like  the  figure,  to  be 
used  in  trimming  specimens. 

A  small  jeweler's  hammer,  for  trying  the  malleability  of 
globules  obtained  by  the  blowpipe,  and  for  other  purposes, 
and  a  small  piece  of  steel  for  an  anvil. 

Two  steel  chisels,  one  six  inches  long,  and  the  other  three. 
When  it  is  desired  to  pry  open  seams  in  rocks  with  the 
larger  chisel,  two  pieces  of  steel  plate  should  be  provided  to 
place  on  opposite  sides  of  the  chisel,  after  an  opening  is  ob- 
tained ;  this  protects  the  chisel  and  diminishes  friction 
while  driving  it. 

For  blasting,  if  this  is  desired  : 

Three  hand-drills  18,  24,  and  36  inches  long,  an  inch  in 
diameter.  The  best  form  is  a  square  bar  of  steel,  with  a 
diagonal  edge  at  one  end.  The  three  are  designed  to  follow 
one  another. 

A  sledge-hammer  of  six  or  eight  pounds  weight,  to  use 
in  driving  the  drill. 

A  sledge-hammer  of  ten  or  twelve  pounds  weight,  for 
breaking  up  the  blasted  rock. 

A  round  iron  spoon,  at  the  end  of  a  wire  fifteen  or  eigh- 
teen inches  long,  for  removing  the  pulverized  rock  from  the 
drill-hole. 


DETERMINATION  OP  MINERALS.  383 

A  crowbar,  a  pickaxe,  and  a  hoe,  for  removing  stones  and 
earth  before  or  after  blasting. 

Cartridges  of  blasting  powder,  to  use  in  wet  holes.  They 
should  one-third  fill  the  drill-hole.  After  the  charge  is  put 
in,  the  hole  should  be  filled  with  sand  and  gravel  alone  with- 
out ramming.  If  any  ramming  material  is  used,  plaster  of 
Paris  is  the  best,  which  has  been  wet  and  afterwards  scraped 
to  a  powder. 

Patent  fuse  for  slow  match,  to  be  inserted  in  the  car- 
tridge, and  to  lead  out  of  the  drill-hole. 

The  table  beyond  is  prepared  especially  to  aid  in  instruc- 
tion, and  comprises,  with  few  exceptions,  only  the  species 
that  are  described  in  large  type  through  the  work,  exclusive 
of  the  hydrocarbon  compounds.  The  following  abbrevia- 
tions are  used  in  it,  in  addition  to  those  explained  on  page 
90.  With  reference  to  colors  :  bnh,  brownish ;  bkh,  black- 
ish ;  gnh,  greenish  ;  gyh,  grayish  ;  rdh,  reddish.  The  acids  : 
nit.,  nitric  acid  ;  sulph.  acid,  sulphuric  acid  ;  HCL,  hydro- 
cloric  acid  ;  sulph.,  sulphurous  or  sulphurous  acid. 

Keactions  :  gelatinizing  with  acid,  see  page  81  ;  reaction 
for  sulphur  with  soda,  see  page  89  ;  blue  or  red  color  with 
cobalt  solution,  see  page  88  ;  hydrous,  yielding  water  in  a 
closed  tube  ;  anhydrous,  not  yielding  water  in  a  closed  tube, 
or  only  traces,  see  page  86  ;  B.B.  lithium-red  color,  see 
page  87  ;  B.B.  yreen  flame  due  to  boron,  see  page  87  ;  coal  is 
used  for  charcoal ;  fus.  for  fusible ;  in/us,  for  infusible ; 
sol.  for  soluble  ;  st.  for  streak. 

In  using  the  blowpipe  it  is  important  to  remember  that 
a  trial  of  fusibility  with  the  forceps,  if  not  at  once  pro- 
ducing fusion,  should  be  made  on  a  piece  of  the  mineral  not 
larger  than  the  fourth  of  an  ordinary  pin-head,  andit'should 
be  either  oblong  and  slender,  or  thin,  and  be  made  to  pro- 
ject considerably  beyond  the  points  of  the  forceps,  lest 
the  forceps  carry  off  the  heat,  and  cause  a  failure  where 
there  ought  to  be  success.  Further,  it  should  be  in  mind, 
that  in  using  charcoal,  a  white  coating  is  always  a  conse- 
quence of  burning  it,  since  the  ash  from  its  own  combustion 
is  white.  Again,  before  testing  for  sulphur  by  means  of 
soda  and  a  polished  surface  of  silver,  it  is  necessary  to  try 
the  flame  and  the  soda  for  sulphur.  Gas-flame  always  con- 
tains traces  of  sulphur,  and  sometimes  too  much  for  safe 
conclusions  in  this  trial. 


384  DETERMINATION  OF   MINERALS. 

A  mineralogist  sometimes  has  occasion  to  measure  dis- 
tances, and  by  the  following  method  he  may  make  himself 
quite  an  accurate  odometer  : 

Let  him  first  find,  or  make,  along  a  roadside,  a  measured 
distance  of  800  to  1,000  feet,  and  then  walk  it  at  his  ordi- 
nary walking  pace  three  or  four  times,  and  note  the  number 
of  steps.  He  will  thus  ascertain  the  actual  length  of  his 
pace,  and  also  find  that  in  his  ordinary  walk  it  does  not 
diifer  much  from  thirty  inches  ;  it  may  be  an  inch  or  two 
less,  or  one,  two,  or  three  more  than  this.  Now  four  times 
thirty  inches  is  ten  feet.  If  then,  as  he  walks,  he  counts 
one  for  every  fourth  step,  each  unit  in  the  count  will  stand 
for  ten  feet  nearly,  and  100,  for  1,000  feet  nearly.  If  his 
pace  is  thirty-one  inches,  let  him  add  a  unit  for  every 
thirty  in  the  counting,  or,  which  is  the  same  thing,  call  his 
thirty  thirty-one,  and  the  needed  correction  will  be  made; 
or  if  his  step  is  twenty-nine  and  one-half  inches,  subtract 
one  from  every  sixty  in  the  counting,  or  in  other  words  du- 
plicate the  sixty.  Or  the  correction  may  be  made  at  the 
end  of  the  pacing  ;  if  at  600,  this  number,  after  adding 
a  thirtieth,  becomes  620  ;  and  the  distance  would  hence  be 
6,200  feet.  With  a  little  practice  the  counting  may  be 
carried  on  almost  unconsciously,  and  when  the  thoughts 
are  elsewhere ;  that  is,  unless  there  is  a  talking  friend  by 
one's  side. 

An  instrument,  called  a  pedometer ',  of  the  shape  and  size 
of  a  small  watch,  is  to  be  had  of  instrument  makers,  which, 
if  carried  in  the  waistcoat  pocket,  will  do  the  registering  for 
the  pedestrian  and  note  the  distance,  without  any  attention 
on  his  part.  But  the  odometer  explained  above,  when  once 
in  working  order,  is  always  at  hand. 


SYNOPSIS  OF  THE  ARRANGEMENT. 
I.  ELEMENTS. 

1.  Lustre  metallic  ;  liquid. 

2.  Lustre  metallic  ;  malleable  and  eminently  sectile. 

3.  Lustre  metallic  ;  brittle  ;    B.B.  on  coal,  wholly  volatile,  with  no 

sulphurous  fumes. 

4.  Lustre  metallic  ;  brittle  ;  H.=l-2  ;  leaves  a  trace  on  paper  ;  B.B. 

on  coal,  infusible,  no  fames  or  odor. 

5.  Unmetallic  ;  burns  readily  with  a  blue  flame. 

6.  Lustre  adamantine  ;  H.  =  10. 


DETERMINATION   OF   MINERALS.  385 

II.    MINERALS  NOT   ELEMENTS,    THAT   B.B.    ON 
COAL  ARE  WHOLLY  VOLATILE. 

1.  Lustre  metallic  ;  streak  metallic. 

2.  Lustre  unmetallic  ;  streak  same  as  color. 

III.  COMPOUNDS,  OF  GOLD,  SILVER,  COPPER, 
LEAD,  TIN,  MERCURY,  CHROMIUM,  COBALT, 
MANGANESE  :  yielding,  on  heating,  a  malleable,  or 
liquid  (for  mercury  ores),  metallic  globule,  as  explained 
on  pages  389-393,  or  else  affording  a  decisive  blowpipe 
reaction,  proving  the  presence  of  one  or  more  of  these 
metals. 

A.  Yielding  a  malleable  globule  B.  B.  on  coal  with,  if  not 
without,  soda. 

1.  Compounds  of  Gold. 

2.  Compounds  of  Silver. 

3.  Compounds  of  Copper. 

4.  Compounds  of  Lead. 

5.  Compounds  of  Tin. 

B.  Yielding  drops  of  mercury  with  soda  in  a  closed  tube. 

1.  Compounds  of  Mercury. 

C.  A  decisive  reaction  with  borax  or  salt  of  phosphorus 
for  chromium,  cobalt,  or  manganese. 

1.  Compounds  of  Chromium. 

2.  Compounds  of  Cobalt. 

3.  Compounds  of  Manganese. 


IV.  MINERALS  OF  METALLIC  OR  SUBMETALLIC 

LUSTRE,  NOT  INCLUDED  IN  PRECEDING 

DIVISIONS. 

1.  Yielding  fumes  in  the  open  tube  or  on  coal,  but  not 
wholly  vaporizable. 


386  DETERMINATION   OF   MINERALS. 

A.  Streak  metallic. 

B.  Streak  unmetallic. 

a.  Fumes  sulphurous  only. 

b.  Fumes  arsenical,  with  or  without  sulphurous. 


2.  Not  yielding  fumes  of  any  kind ;  streak  unmetallic. 

A.  B.B.  easily  fusible,  giving  a  magnetic  bead  ;  lustre  sub 

metallic. 

B.  Infusible,  or  nearly  so. 

a.  Reaction  for  iron  ;  anhydrous. 

b.  Reaction  for  iron  ;  hydrous. 

c.  Reaction  for  chromium  or  titanium, 

d.  Reaction  for  osmium  with  nitre. 


V.  MINERALS  OF  UNMETALLIC  LUSTEE. 

1.  Having  an  acid,  alkaline,  alum-like,  or  styptic  taste. 

A.  CARBONATES  :  Taste  alkaline  ;  effervescing  with  HC1. 

B.  SULPHATES :  No  effervescence  ;  reaction  for  sulphur 

with  soda.  » 

C.  NITRATES  :   With  sulph.  acid,  reddish  acrid  fumes ; 

no  action  with  HC1  ;  deflagrate. 

D.  CHLORIDES  :    With  sulph.  acid,  acrid  fumes  of  HC1 ; 

no  fumes  with  HC1. 

E.  BORATES  :  No  effervescence  ;  reaction  for  boron  when 

moistened  with  sulph  acid. 


2.  Not  haying  either  of  the   above-mentioned  kinds  of 
taste. 

A.  CARBONATES  :  Effervescing  with  HC1. 

a.  Infusible  ;  assay  alkaline  after  ignition. 

b.  Infusible  ;    become  magnetic  and  not  alkaline,  on 

ignition. 

c.  Infusible ;    B.B.    on    coal    with    soda,    zinc    oxide 

vapors. 

d.  Infusible  ;  B.B.  on  coal  reaction  for  nickel. 

e.  Fusible  ;  assay  alkaline  after  ignition. 


B.  SULPHATES  :  Reaction  for  sulphur  with  soda, 

a.  Fusible  ;  assay  alkaline  after  fusion. 

b.  Fusible  ;  reaction  for  iron. 

c.  Infusible. 


DETERMINATION   OP   MINERALS.  387 

C.  ARSENATES  :  on  coal  arsenical  fumes. 

D.  SILICATES,  PHOSPHATES,  OXIDES  : 

Species  not  included  in  the  preceding  subdivisions. 

X.    STREAK  DEEP  RED,  YELLOW,  BROWNISH-YELLOW,  GREEN,  OB 
BLACK. 

A.  Infusible,  or  fusible  with  difficulty. 

B.  Fusible  without  much  difficulty. 

H.    STREAK   GRAYISH  OR  NOT  COLORED. 

1.  Infusible. 

A.  Gelatinize  with  acid,  forming  a  stiff  jelly. 

B.  Not  forming  a  stiff  jelly  ;  hydrous. 

a.  Blue  color  with  cobalt  solution. 

6.   Reddish  or  pink  color  with  cobalt  solution. 

c.    Not  blue  or  red  with  cobalt  solution. 

C.  Not  forming  a  stiff  jelly  ;  anhydrous. 

a.  Blue  color  with  cobalt  solution. 

b.  Not  blue  or  reddish  color  with  cobalt  solution. 

2.  Fusible  with  more  or  less  difficulty. 

A.  Gelatinize  and  form  a  stiff  jelly. 

a.  Hydrous  ;  fuse  easily. 

b.  Hydrous  ;  fuse  with  much  difficulty. 

c.  Anhydrous. 

a.  No  reaction  for  sulphur ;  no  coating  on  coal. 
ft.  Reaction  for  sulphur  with  soda. 

B.  Not  gelatinizing. 

1.  Structure  eminently  micaceous  ;  folia  tough,  pearly, 

and  H.  of  surface  of  folia  not  over  3*5  ;  anhydrous 
or  hydrous. 

2.  Structure  not  eminently  micaceous. 

a.  Hydrous. 

a.  No  reaction  for  phosphorus,  or  boron. 

|.  H.  =1  to  3  ;  lustre  not  at  all  vitreous. 
ff.  H.=3-5-6'5;   lustre  of  cleavage  sur- 
face sometimes  pearly  ;  elsewhere  vi- 
treous. 
ft.  Reaction  for  phosphorus  or  boron. 

b.  Anhydrous. 

a.  B.B.  lithium-red  flame. 

ft.  B.B.  boron  reaction  (green  flame). 

y.  B.B.  reaction  for  titanium. 

8.  B.  B.  reaction  for  fluorine  or  phosphorus. 

e.  B.B.  reaction  for  iron. 

£.  B.B.  no  reaction  for  iron :  not  of  the  pre- 
ceding subdivisions. 


388  DETERMINATION   OP  MINERALS. 

I.  ELEMENTS. 

1.  Lustre  metallic  ;  liquid. 

MERCURY,  p.  128.  This  is  the  only  metallic  mineral  which  is  liquid 
at  the  ordinary  temperature  and  atmospheric  pressure. 

2.  Lustre  metallic  ;  malleable  and  eminently  sectile. 

GOLD,  p.  109.     G.  =15-19-5  ;  yellow  ;  fusible  ;  not  sol.  in  nitric  acid 

or  HC1,  but  sol.  in  aqua  regia. 
PLATINUM,  p.  124.     G.=  16-19  ;  nearly  white  ;  infusible  ;  insol.  in 

nitric  acid. 
PALLADIUM,  p.  127.     G.=ll-8-ll-8  ;  grayish-white  ;  diff.  fusible  ; 

sol.  in  nitric  acid. 
SILVER,  p.  116.      G.  =10-11-1 ;  white  ;  fusible  ;  sol.  in  nitric  acid, 

and  deposited  again  on  copper. 
COPPER,  p.  131.      G.=r8'84;   copper-red;  fus.;  sol.  in  nitric  acid, 

and  the  solution  becomes  sky-blue  when  ammonia  is  added 
IRON,  p.  171.     G.— 7-3-7-8;  iron-gray;  attracted  by  the  magnet. 

The  only  other  mineral  of  metallic  lustre  that  is  also  malleable  and 
eminently  sectile  is  argentite,  a  silver  sulphide,  along  with  two  others 
of  like  composition  but  different  crystallization. 

3.  Lustre  metallic  ;  brittle ;    B.B.   wholly  volatile, 

but  give  off  no  sulphurous  fumes. 

BISMUTH,  p.  101.     G.=9  73  ;  reddish- white  ;  on  coal  a  yellow  coat- 
ing ;  fumes  inod. 

ANTIMONY,  p.  100.    G.  =6'6-6'7;  tin-white  ;  fumes  dense  wh.,  inod. 

ARSENIC,  p.  98.     G.=r5'9-6  ;  tin-white  ;  fumes  white,  alliaceous. 

TELLURIUM,  p.  96.     G.=6'l-6'3  ;  tin- white  ;  fus.;  fumes  white  ; 
flame  green. 
The  only  other  mineral  that  is  wholly  volatile,  and  also  gives  off  no 

sulphurous  fumes,  is  allemontite,  an  antimony  arsenide. 

4.  Lustre  metallic  ;  H.  =1-2  ;  B.B.  on  coal  infusible  ; 

no  fumes. 

GRAPHITE,  p.  107. 

5.  Lustre  unmetallic  ;  takes  fire  readily  in  the  flame 

of  a  candle,  and  burns  with  a  blue  flame. 

SULPHUR,  p.  94. 

6.  Lustre  adamantine  ;  EL  =10. 

DIAMOND,  p.  103.     Easily  scratches  corundum  or  sapphire. 


DETERMINATION   OP   MINERALS.  389 

II.    MINEKALS,    NOT    ELEMENTS,    THAT 
ARE   WHOLLY  VOLATILE  B.B. 
ON   COAL. 

1.  Lustre  metallic  ;  streak  metallic. 

TETRADYMITE,  p.  102.  G.— 7 2-7 '9  ;  pale  steel-gray;  so  soft  as 
to  soil  paper  ;  on  coal  white  fumes  ;  flame  bluish-green;  sometimes 
sulph.  odor  ;  in  open  tube,  a  coating  which  fuses  to  white  drops. 

BISMUTHINITE,  p.  102.  G.^6'4-7'2;  whitish  lead-gray;  on  coal 
yellow  coating  and  sulph.  odor. 

STEBNITE,  p.  100.  G.  =4-5-4  52  ;  lead-gray;  on  coal  dense  wh. 
fumes  and  wh.  coating . 

2.  Lustre  unmetallic  ;  streak  same  nearly  as  color. 

ORPIMENT,  p.  99.     Lemon  yellow  ;  on  coal  burns,  odor  alliaceous. 
REALGAR,  p.  99.     Bright  red  ;  on  coal  burns,  odor  alliaceous. 
ARSENOLITE,  p.  99.     White  ;  on  coal,  odor  alliaceous. 
VALENTINITE,  p.  101.     White  ;  on  coal  dense  wh.  fumes,  inott. 
CINNABAR,  p.  128.     Red ;   in  open  tube,  sulph.  odor,  coating  of 

mercury  globules. 
SALMIAK,  p.  230.  White  ;  saline  and  pungent  taste  ;  on  coal,  fumes 

of  ammonia. 


III.  COMPOUNDS  OF  GOLD,  SILVER,  MER- 
CURY, COPPER,  LEAD,  TIN,    CHRO- 
MIUM, COBALT,  MANGANESE. 

A.  Yielding  a  malleable  globule  B.B.  on  coal,  with 
or  without  soda 

1.  COMPOUNDS  OF  GOLD. 

Yield  gold,  or  an  alloy  of  gold  and  silver,  B.B.  on  coal.  The  TELLTJ- 
KIUM  ORES,  pp.  115,  116,  give  a  coating  of  drops  of  tellurous  acid  in 
open  tube. 

2.  COMPOUNDS   OP  SILVER. 

B.B.  easily  fusible  ;  G.  above  5  ;  yield,  with  few  exceptions,  a  glo- 
bule of  silver  (white  and  malleable),  on  coal,  with  soda,  if  not  without  ; 
and,  in  the  exceptions,  silver  globule  obtained  by  cupellation.  All 
have  metallic  lustre  excepting  cerargyrite,  bromyrite,  and  iodyrite. 


390  DETERMINATION   OF    MINERALS. 

a.    EMINENTLY  SECTILE. 

ARGENTTTE,  p.  117.     G.=7'2-7'4;  lustre  metallic  ;  on  coal  sulph. 

fumes. 
CERARGYRITE,  p.  120.     G.  =5 '3-5  "6;  lustre  like  that  of  white, 

gray,  or  greenish  to  brownish  wax. 

&.    NOT  SECTILE  ;    ON  COAL  ODOROUS  FUMES. 

SULPHIDES,  p.  118.     Gives  sulph.  odor. 
ARSENICAL  ORES,  pp.  119,  120.     Alliaceous  fumes. 
SELENIDES,  p.  118.     Horse-radish  odor. 


C.   NOT  SECTILE  ;    ON  COAL  FUMES  OF  ANTIMONY  OR  TELLURIUM. 

ANTIMONIAL  ORES,  pp.  119,  120.  Dense  white  fumes  of  anti- 
mony; with  also,  if  sulphur  is  present,  sulph.  fumes.  • 

TELLURIDES,  p.  118.  In  open  tube  coating  which  fuses  to  drops 
of  tellurous  acid. 

STROMEYERITE,  p.  119.  Contains  copper,  and  requires  cupellation 
in  order  to  obtain  a  globule  of  silver. 

3.  COMPOUNDS  OF  COPPER. 

Unless  iron  is  present,  a  globule  of  metallic  copper  is  obtained  with 
soda,  if  not  without,  on  coal;  with  a  nitric  acid  solution  and  ammonia 
in  excess  a  bright  blue  color;  moistened  with  HC1  the  blue  flame  of 
chloride  of  copper;  and  a  clean  surface  of  iron  in  the  nitric  solu- 
tion becomes  coated  with  copper. 

1.   METALLIC  LUSTRE. 

SULPHIDES,  pp.  132-136.     On  coal  or  in  open  tube  sulph.  fumes. 
ARSENIDES,  SELENIDES,  p.  135. 
ANTIMONIAL  SULPHIDES,  p.  135,  136. 

2.     LUSTRE    UNMET  AL]£c  ;    B.B.    NEITHER    ON     COAL     NOR    IN     OPEN 
TUBE  ANY  ODOROUS   FUMES  ;   NO  TASTE. 

CUPRITE,  p.  136.  H.  =3'5-4;  G.=5'8-6'2;  isometric;  deep  red,  streak 

bnh-red. 
ATACAMITE,  p.  136.     Darkish  bright  green,  streak  gnh;  B.B.  on 

coal  fuses,  coloring  O.P.  azure-blue,  with  a  green  edge  ;  easily  sol. 

in  acids. 

PHOSPHATES,  p.  139. 
MALACHITE,  p.  140.   H.=3-4;  G.=3'7-4;  light  to  deep  green;  ef~ 

fervesces  with  HC1. 
AZURITE,  p.  141.     H.  =3  5-4-5;  G.=3  5-3'9;  deep  blue  ;  effervesces 

with  HC1. 
DIOPTASE,  p.  141.      H.=5;  G.  =3  25-3  35;  emerald-green;  B.B.  in- 

fusible. 
CHRYSOCOLLA,  p.  142.     Bluish-green;  B.B.  infusible. 


DETERMINATION   OF   MINERALS.  391 

3.   LUSTRE  T7NMETALLIC;  B.B.  ON  COAL,  OR  IN  CLOSED  TUBE,  ODOROUS 
FUMES  OF  ARSENIC  OR  SULPHUR,  OR  REACTION  FOR  SULPHUR. 

ARSENATES,  p.  189.     On  coal  arsenical  fumes. 
CHALCANTHITEj  p.  137.     Blue;  taste  nauseous;  astringent. 

Also  Stromeyerite,  Stannite,  Bournonite  give  reactions  for  copper. 

4.  COMPOUNDS  OF  LEAD. 

Yield  B.B.  on  coal  a  dark  lemon-yellow  coating ;  finally,  with  soda, 
if  not  without,  a  globule  (metallic  and  malleable)  of  lead  is  ob- 
tained ;  but  by  continued  blowing  with  O.F.  the  lead  all  goes  off  in 
fumes,  leaving  other  more  stable  metals  (silver,  etc.)  behind.  Sul- 
phurous, selenious  and  tellurous  fumes  easily  obtained  either  on 
coal  or  in  an  open  tube  from  the  sulphide,  selenide,  tellurides  ;  and 
arsenical  or  antimonial  fumes  from  ores  containing  arsenic  or  anti- 
mony. None  have  taste. 

1.   LUSTRE  METALLIC. 

GALENITE,  p.  145.  H.  =2*5  ;  O.  =7*2-7 "7  ;  cleavage  cubic  eminent ; 
lead-gray,  streak  same  ;  in  open  tube  sulph. 

SELENIDES,  TELLURIDES,  ANTIMONIAL  and  ARSEN- 
ICAL SULPHIDES,  page  149. 


2.    LUSTRE    UNMET ALLIC  ;    NO    ODOROUS    FUMES,    OR    REACTION    FOR 

SULPHUR. 

MINIUM,  p.  149.     Bright  red,  streak  same. 

CROCOITE,  p.  150.     Monoclinic  ;  bright  red,  streak  orange-yellow  ; 

B.B.  with  salt  of  phosphorus  emerald-green  bead. 
PYROMORPHITE,   p.  151.     Hexagonal ;   bright  green  to  brown, 

rarely   orange-yellow  ;  streak  white.     B.B.    fuses  easily,   coloring 

flame  bluish-green. 
CERUSSITE,    p.    152.      Trimetric,    often    in    twins;    H.=3-3'5; 

G.=6'4-68;    white,    gyh  ;  lustre   adamantine;   often  tarnished  to 

grayish  metallic  adamantine.     Effervesces  in  dilute  nitric  acid. 


3.    UNMETALLIC  ;    REACTION  FOR  SULPHUR. 

ANGLE  SITE,  page  150.  Trimetric  ;  white,  gyh  ;  fuses  in  flame  of 
candle  ;  B.B.  reaction  for  sulphur  ;  no  effervescence  with  acids. 

5.  COMPOUNDS   OF  TIN. 

CASSITERITE,  p.  160.  H.=6-7  ;  G.  =6 '4-7-1  ;  brown,  gyh,  ywh, 
black;  B.B.  infusible;  on  coal  with  soda  a  globule  of  tin,  yield 
no  fumes. 

Stannite,  p.  158.     A  copper,  iron,  and  tin  sulphide,  does  not  give 
B.B.  a  metallic  malleable  globule. 


392  DETERMINATION   OP   MINERALS. 

B.   Yield  drops  of  mercury  in   closed  tube  with   or 
without  soda. 

COMPOUNDS  OP  MERCURY. 

CINNABAR,  p.  128.  H.=2-2  5  ;  G.=8-9  ;  bright  red,  bnh  red,  gyh  ; 

streak  scarlet. 
AMALGAM,  p.  117.     H.  =3-3-5  ;   G. = 13-14  ;   silver-white;  yields 

silver  B.B.  on  coal. 
Spaniolite,  p.  136,  a  variety  of  tetrahedrite,  yields  mercury. 


C.  No  malleable  globule  ;  decisive  reaction  with  borax 

or  salt  of  phosphorus  for  chromium,  cobalt,  or 

manganese. 

1.  COMPOUNDS  OF  CHROMIUM. 
Give  with  borax  an  emerald-green  bead  in  both  flames. 

CHROMITE,  p.  180.  H.=5'5  ;  G.=4'3-4'5;  isometric,  often  m 
octahedrons,  massive  ;  submetallic  ;  bnh  iron-black,  streak  brown  ; 
B.B.  on  coal  becomes  magnetic  ;  with  borax,  a  bead  which  is 
emerald-green  on  cooling. 

CROCOITE,  p.  150.  H.-25-3;  O.=5'9-6'l;  bright  red,  streak 
orange  ;  B.B.  fuses  very  easily,  on  coal  globule  of  lead,  and  with 
salt  of  phosphorus  emerald-green  bead.  PhcBnicochroite  and  Vauque- 
Unite  are  other  lead  chromates. 

2.    COMPOUNDS  OF  COBALT. 

Give  a  blue  color  with  borax  after,  if  not  before,  roasting. 

[When  much  nickel  or  iron  is  present  the  blue  color  is  not  ob- 
tained ;  and  species  or  varieties  of  this  kind  are  not  here  included.] 

1.   LUSTRE  METALLIC. 

COBALTTTE,  p.  165.  H.—  55;  G.=6-6'3;  isometric  and  pyrito- 
hedral  ;  rdh  silver- white,  streak  grayish -black  ;  B.B.  on  coal  sulph. 
and  arsen.  fumes,  and  a  magnetic  globule. 

SMALTITE,  p.  1G5.  H.=5'5-6;  G.rr6'4-7'2;  tin-white,  streak 
gyh  black  ;  B.B.  on  coal  alliaceous  fumes  ;  most  varieties  fail  to  give 
the  blue  color  immediately  with  borax,  because  of  the  iron  and 
nickel  present. 

LINNJEITE,  p.  164.  H.=5'5;  G.=4'8-5;  isometric;  pale  steel- 
gray,  copper-red  tarnish,  streak  bkh  gray.  B.B.  on  coal  sulph. 
fumes. 

2.   LUSTRE  UNMETALLIC. 

ERYTHRITE,  p.  167.  H.  =  l  5-25  ;  G.=295;  monoclinic,  one 
highly  perfect  cleavage,  also  earthy  ;  rose-red,  peach-blossom  red, 
streak  reddish  ;  B.B.  fuses  easily  ;  yields  water. 


DETERMINATION  OF  MINERALS.  393 

BIEBERITE,  p.  168.     A  cobalt  sulphate. 
REMINGTONITB,  p.  168.     A  hydrous  cobalt  carbonate. 

.3.  COMPOUNDS    OF  MANGANESE. 

Give  an  amethystine  globule  in  O.F.  with  borax.  [The  globule 
looks  black  if  too  much  of  the  manganese  mineral  is  used,  and  with 
a  large  excess  may  be  opaque.] 

1.    GIVES  OFF  CARBONIC   ACID   WHEN   TREATED  WITH    DILUTE  H  Cl  ; 
LUSTRE  UNMETALLIC. 

RHODOCHROSITE,  p.  191.     H.=35-4'5  ;  G.  =3  4^3  7  ;  rose-red. 

Also  manganese-bearing  varieties  of  calcite,  dolomite,  ankerite,  side- 
rite,  all  of  which  have  the  cleavage  and  general  form  of  rhodochro- 
site  ;  when  containing  a  few  per  cent,  of  manganese  they  often  turn 
black  on  exposure. 

2.   TREATED    WITH  H  Cl    YIELDS    CHLORINE   FUMES. 

MANGANITE,  p.  189.  H.=4;  G.=4'2-4'4;  in  oblong  trimetric 
prisms  ;  grayish-black,  streak  reddish-brown  ;  lustre  submetallic  ; 
B.  B.  infusible  ;  yields  water. 

PSILOMELANE, p.  189.  H.=5-7  ;  G.  =3-7-4'7  ;  amorphous  ;  black, 
streak  brownish-black  ;  submetallic  ;  B.B.  infusible  ;  yields  water. 
Wad  is  similar,  but  often  contains  cobalt. 

PYROLUSITE,  p.  188.  H.— 2-2  5  ;  G.=4'82  ;  in  stoutish  trimetric 
crystals ;  metallic ;  dark  steel-gray,  streak  black  or  bluish-black  ; 
B.B.  infusible  ;  yields  no  water. 

BRAUNITE  and  HAUSMANNITE  (p.  189)  are  other  anhydrous 
manganese  oxides. 

FRANKLINITE,  p.  179.  H.  =5-5-6  5;  G.=5-5'l  ;  in  octahedrons 
and  massive  ;  iron-black,  streak  dark  reddish  brown ;  B.B.  infusi- 
ble ;  but  little  chlorine  with  H  Cl. 

8.    C02   OR   Cl  NOT    GIVEN    OFF  WHEN  TREATED  WITH  HC1; 
AN  HYDROUS. 

RHODONITE,  p.  247.     H.=5'5-6'5;  G.  =3  4-3  68;  rose-red;  B.B. 

fuses  easily. 
TRIPLITE,  p.  191.     H.=5-5;  G.=3'4-3'8;  brown  to  black;  B.B. 

fuses  very  easily,  globule  magnetic  ;  sol.  in  H  Cl. 
HELVITE,  p.  256.     H.=6-65;  G.  =3  1-3  3;  in  yellowish  tetrahe- 

hedrons  ;  B.  B.  fuses  easily. 
SPESSARTITE  (Manganesian  Garnet),  p.  258.     H.  =6'5-7  ;  G  =3'7- 

4*4 ;    in   dodecahedrons   and  trapezohedrons ;    red,  brownish-red  ; 

B.B.  fuses  easily. 
TEPHROITE,   p.  256.     H.=5'5-6;  G.=4-4'12;  reddish  to  brown 

and_gray  ;  B.B.  fuses  not  very  easily  ;  gelat.  in  H  Cl. 
Mite,  p.  256,  is  related,  and  also  gelatinizes. 


394  DETERMINATION  OF  MINERALS. 

HAUERITE,  p.  188.     H.=4;  G.=3'46;  isometric;  reddish  brown, 

streak  brownish-red.     B.B.  yields  sulphur,  after  roasting  reaction 

for  manganese. 
ALABANDITE,  p.  188.     H.  =3'5-4  ;  G.  =4 ;  submetallic,  iron-black; 

streak  green ;  B.B.   on  coal  sulphur,  after  roasting  reaction  for 

manganese. 

Vesuvianite,  epidote,  axinite,  ilvaite,  gothite,  include  varieties  that 
give  reaction  for  manganese. 


IV.    MINERALS  OF  METALLIC   OR   SUB- 

METALLIC  LUSTRE  NOT  INCLUDED 

IN  PRECEDING  DIVISIONS. 


1.  YIELDING  FUMES  IN  THE  OPEN  TUBE 

OR  ON  COAL,  BUT  NOT  WHOLLY 

VAPORIZABLE. 

A.  STREAK  METALLIC. 

MOLYBDENITE,  p.  96.  H.=l-l-5;  G.=4'4-4'8 ;  lead-gray,  and 
leaves  trace  on  paper  ;  B.B.  on  coal  sulphurous  fumes 

PISMUTHINITE,  p.  102.  H.  =2  ;  G.=6'4-7'2  ;  lead  gray,  whitish  ; 
B.B.  on  coal  sulphurous  fumes,  and  yellow  bismuth  oxide  ;  sol.  in 
hot  nitric  acid  and  a  white  precip.  on  diluting  with  water 

B.  STREAK  UNMETALLIC. 

a.   FUMES   SULPHUROUS  ONLY. 

PYRITE,  p.  172.  H.— 6-6-5;  G.=4'8-5'2:  isometric  and  pyritohe- 
dral ;  pale  brass-yellow,  streak  gnh  black,  bnh  black  ;  B.B.  on 
coal,  fuses  to  a  magnetic  globule. 

MARCASITE,  p.  174.  H.=6-6'5;  G.-4-68-485;  trimetric ;  pale 
bronze-yellow  ;  streak  gyh  black,  bnh  black  ;  B.B.  like  pyrite. 

PYRRHOTITE,  p.  174.  H.=3'5-4-5;  G.  =4  4-4 -68;  hexagonal; 
bronze-yellow,  rdh  ;  streak  gyh  black;  slightly  magnetic;  B.B. 
fuses  to  a  magnetic  mass. 

MILLERITE,  p.  164.  H.=3-3'5;  G.=4'6-5'7,  rhombohedral, 
usually  in  acicular  or  capillary  forms,  also  in  fibrous  crusts  ;  brass- 
yellow,  somewhat  bronze-like  ;  B.B.  fuses  to  a  globule,  reacts  for 
nickel. 

LINNJEITE.  p.  164.  H.=5'5  :  G.=4'8-5  ;  isometric;  pale  steel- 
gray,  copper-red  tarnish  ;  streak  blackish -gray  ;  B.B.  on  coal  fuses 


DETERMINATION   OF   MINERALS.  395 

to  a  magnetic  globule,  after  roasting  gives  reactions  for  nickel, 
cobalt,  and  iron. 

SPHALERITE,  p.  154.  H.-35-4;  G.=3'94'2;  isometric;  lustre 
submetallic  ;  streak  nearly  uncolored  ;  nearly  infusible  alone  and 
with  borax  ;  on  coal  a  coating  of  zinc  oxide. 

b.    ARSENICAL  FUMES,  WITH  OR  WITHOUT  SULPHUROUS. 

ARSENOPYRITE,  p.  175.  H.=5-6  ;  G.=6-6'4  ;  trimetric  ;  white, 
gyb,  streak  dark  gyh  black.  In  closed  tube,  red  arsenic  sulphide 
and  metallic  arsenic ;  B.B.  on  coal  fuses  to  magnetic  globule. 

GERSDORFFITE,  p.  166.  H.^5'5  ;  G.=5'6-6'9  ;  isometric,  py- 
ritohedral ;  white,  gyh,  streak  grayish -black.  In  closed  tube 
arsenic  sulphide,  on  coal  not  magnetic,  and  reacts  for  nickel  and 
often  cobalt. 

NICCOLITE,  p.  166.  H.=5-5'5;  G.  =7 '3-7 -7,*  hexagonal  ;  pale 
copper-red,  streak  pale  bnh  black ;  in  open  tube,  coating  of  arsen- 
ous  acid  ;  B.B.  on  coal  no  sulph.  fumes,  fuses  to  globule  which  re- 
acts for  iron,  cobalt  and  nickel. 

SMALTITE,  p.  165.  H.=:5'5-6  ;  G.  =6-4-7 '2  ;  isometric  ;  tin-white  ; 
streak  gyh  black  ;  on  coal,  no  fumes  of  sulphur  or  only  in  traces. 


2.  NOT  YIELDING  FUMES  OF  ANY  KIND. 
STEEAK  UNMETALLIC. 

A.   B.B.  EASILY  FUSIBLE,  AND  GIVING  A  MAGNETIC  BEAD. 
LUSTRE  SUBMETALLIC. 

ILVAITE,  p.  263.  H.=5'5-6;  G.=3'7-4'2  ;  trimetric;  gyh  iron- 
black,  streak  gnh  or  bnh  black  ;  gelat.  with  H  Cl. 

ALLANITE,  p.  263.  H.  =5'5-6  ;  G.=3  4  2  ;  monoclinic ;  bnh  pitch- 
black,  streak  gyh,  bnh  ;  B.B.  fuses  easily ;  most  varieties  gelat. 
withHCl. 

WOLFRAMITE,  p,  183.  H.=5-5'5;  G.=7'l-7'6;  monoclinic;  gyh 
black  or  bnh  black  ;  B.B.  fuses  easily,  and  reacts  for  iron,  manga- 
nese, and  tungsten. 

B.    INFUSIBLE  OR  NEARLY  SO. 

a.  REACTION  FOR  IRON  ;    ANHYDROUS;  H.=5-6'5. 

MAGNETITE,  p.  178.     G.=4'9-5'2  ;  isometric  ;  iron-black  ;  streak 

black  ;  strongly  magnetic. 
MENACCANITE,  p.  178.     G.  =4*5-5  ;  rhombohedral  ;  iron-black  : 

streak  submetallic,  black  to  bnh  red  ;  very  slightly  magnetic. 
HEMATITE,  p.  176.     G.=4'5-5'3;    rhombohedral ;  gyh  iron-black, 

in  very  thin   splinters  or  scales  blood-red   by  transmitted  light; 

streak  red  ;  sometimes  slightly  magnetic. 
MARTITE,  p.  177.     Same  as  hematite,  but  isometric. 
TANTALITE,  p.  184.    G.=7-8;  trimetric;  iron-black,  streak  rdh 

brown  to  black. 


396  DETERMINATION    OF   MINERALS. 

FRANKLINITE,  p.  179.  H.=5'5-6'5;  G.=4'8-5'l  ;  octahedral, 
massive  ;  iron-black  ;  streak  dark  rdli  brown ;  slightly  attracted 
by  magnet  ;  with  soda  reaction  for  manganese. 

COLUMBITE,  p.  183.  G.  =5' 4-6  5;  trimetric  ;  iron-black,  gyh 
black,  streak  dark  red  to  black,  often  with  a  bluish  steel -tarnish. 

SAMARSKITB,  p.  202.  H.=5'5-7;  G.=5'6-58;  velvet-black, 
pitch-black  ;  streak  dark  rdh  brown  ;  B.B.  glows  ;  fuses  with  dif- 
ficulty. 

b.    REACTION  FOR  IRON  J    HYDROUS  ;  LUSTRE   SUBMETALLIC. 

LIMONITE,  p.  181.  G.  =3-6-4  ;  massive,  often  stalactitic  and  tube- 
rose with  surface  sometimes  highly  lustrous,  often  subfibrous  in 
structure  ;  black,  bnh  black  ;  streak  bnh  yellow. 

GOTHITE,  p.  182.  G.=4'0-4-4;  trimetric;  also  fibrous  and  mas- 
sive ;  bkh  brown  ;  streak  bnh  yellow. 

TURGITE,  p.  182.  G.-3-6-4'68  ;  fibrous  and  massive,  looking  like 
limonite  ;  black,  rdh  black,  streak  red  ;  in  closed  tube  decrepitates, 
which  is  not  the  case  with  gothite  and  limonite. 

C.    REACTION  FOR  CHROMIUM  OR  TITANIUM. 

CHROMITE,  p.   180.     H.=5-5;  G.=4'3-4'6;  isometric;  submetal- 

lic  ;  bnh  iron-black,  streak  brown  ;   B.B.  with  borax  gives  a  bead 

which  on  cooling  is  chrome-green. 
RUTILE,    p.   162.     H.  =6-65;    G.=418-4-25 ;    black,  streak  bnh; 

reacts  for  titanium.     Black  varieties  of  brookite  (p.  163),  submetallic 

in  lustre,  give  same  reaction. 

Euxenite,  p.  202  ;  yttrotantalite,  p.  202  ;  cescliynite,  p.  202 ;  ferguson- 
ite,  p.  202,  and perofskite,  p.  163,  are  submetallic  in  lustre. 

d.    HEATED   WITH    NITRE   IN  A   MATRASS   YIELDS    FUMES  OF  OSMIUM. 

IRIDOSMINE,  p.  127.  H.=6-7;  G.  =19-21 -2  ;  in  small  scales 
from  auriferous  or  platiniferous  sands  ;  tin- white,  gyh. 


V.  LUSTKE  UNMETALLIC. 


1.  MINERALS  HAYING  AN  ACID,  ALKALINE, 
ALUM-LIKE,  OR  STYPTIC  TASTE. 

A.  CARBONATES  :  Taste  alkaline  ;  effervescing  with  HC1. 

NATRON,  p.  229.     Effloresces  on  exposure. 
TRONA,  p.  230.     Does  not  effloresce. 


DETERMINATION   OF   MINERALS.  397 

B.  SULPHATES  :  No  effervescence;  reaction  B.B.  on  coal  with  soda 

for  sulphur. 

MASCAGNITE,  p.  231.     Yields  ammonia. 

MIRABIL1TE,    p.    226.      Monoclinic,    crystals  stout ;     taste    cool, 

saline,  bitter  ;  B.B.  flame  deep  yellow. 
EPSOMITU,  p.  205.    Trhnetric,  crystals  ordinarily  slender,  spicule- 

like  ;  taste  bitter  and  saline  ;   B.B.' flame  not  yellow. 
ALUNOGOEN,  p.  197.     Taste  like  common  alum. 
KALINITE,  MENDOZ1TE  and  other  alums,  p.  198. 
MELANTERITE,  p.  182.    Green  ;  taste  styptic  ;  reacts  for  iron. 
CHALCANTHITE,  p.  137.     Blue  ;  reacts  for  copper. 
MORENOSITE,  p.  168.     Green  ;  reacts  for  nickel. 
BIEBERITE,  p.  168.     Reddish  ;  reacts  for  cobalt. 
GOSLARITE,  p.  156.     White  ;  reacts  for  zinc. 
JOHANNITE,  p.  171.     Emerald-green,  reacts  for  uranium. 

C.  NITRATES  :  With  sulphuric  acid,  reddish  acrid  fumes  ;  no  action 

with  hydrochloric  acid  ;  deflagrate. 

NITRE,  p.  228.     Not  efflorescent.     Strong  deflagration. 
SODA-NITRE,  p.  229.     Efflorescent. 
NITROCALCITE,  p.  214.     Deflagration  slight. 

D.  CHLORIDES  :  With  sulphuric  acid  acrid  fumes  of  HC1 ;  no  fumes 

with  HC1. 

S  ALMIAK,  p.  230.  Taste  saline,  pungent ;  on  coal,  evaporates  ;  with 

soda,  odor  of  ammonia. 

SYLVITE,  p.  224.     Taste  saline  ;  B.B.  flame  purplish. 
HALITE   or  COMMON  SALT,  p.  224.     Taste  saline ;  B.B.  flame 

yellow. 

E.  BORATES.    No  effervescence  with  acids  ;  B.  B.  reaction  for  boron, 

when  moistened  with  sulphuric  acid. 

SASSOLITE,  p.  97.      Taste  feebly  acid  ;  B.B.  very  fusible. 
BORAX,  p.  227.     Taste  sweetish  alkaline  ;  B.B.  puffs  up. 


2.    MINEKALS  NOT  HAYING  AN  ACID,  ALKA- 
LINE, ALUM-LIKE  OR  STYPTIC  TASTE. 

A.  CARBONATES  :  Effervescing  with  HCL 

A.    INFUSIBLE      ASSAY  ALKALINE  AFTER  IGNITION. 


p.  215.  H.  under  .3  '5  ;  G.=2'5-2'72;  ft  A  R=W5°  5', 
with  three  easy  cleavages  parallel  to  E;  colors  various  ;  effervesces 
readily  with  cold  HC1  ;  anhydrous. 


398  DETERMINATION    OF    MINERALS. 

ARAGONITE,  p.  218.  H.=3'5-4;  G.=2.94;  trimetric,  cleavage  im- 
perfect ;  otherwise  like  calcite. 

DOLOMITE,  p.  219.  H.=3'5-4  ;  G.rr2'8-2'9  ;  rliombohedral,  Rf\R 
=106  15'  ;  colors  various  ;  effervesces  but  slightly  with  cold  HC1, 
unless  finely  pulverized  ;  anhydrous. 

MAGNESITE,  p.  207.  H.  =3  5-4'5  ;  G.  =3-3'l  ;  rhombohedral,  #  A  ,R 
=107°  29'  ;  white,  ywh,  gyh  ;  effervesces  but  slightly  with  cold 
HC1 ;  anhydrous. 

HYDROMAGNESITE,  p.  207.  H.=l-3  5  ;  G.r=2  14-218  ;  hydrous. 


B.    INFUSIBLE  ;   BECOME   MAGNETIC   AND  NOT  ALKALINE  AFTER 
IGNITION. 

SIDERITE,  p.  185.  H.  =3  5-4 -5  ;  G.=3'7-3'9  ;  rhombohedral,  R  :R 
=107°  ;  cleavage  as  in  calcite  ;  becomes  brown  on  exposure,  chang- 
ing to  limonitf. 

ANKERITE,  p.  186.  H.=3'5-4;  G.=2'9-3'l;  #AjR=106°  7'  ;  be- 
comes brown  on  exposure. 

Some  kinds  of  calcite  and  dolomite  contain  iron  enough  to  become 
magnetic  on  ignition. 


C.    INFUSIBLE  ;    B.B.  ON   COAL  WITH   SODA,  COATING  OF  ZINC   OXIDE. 

SMITHSONITE,  p.  156.  H.=5;  G.=4-45;  rhombohedral  like 
calcite;  R/\R—\QT  40'  ;  crystals  often  an  acute  rhombohedron  ; 
anhydrous. 

HYDROZINCITE,  p.  157.  H.=2-2'5;  G.^3'6-3'8;  white,  gyh, 
ywh,  often  earthy  ;  reacts  for  zinc  ;  hydrous. 


D.    INFUSIBLE  ;  B.B.  ON  COAL  REACTION  FOR  NICKEL. 

ZARATITE  (Emerald  nickel),  p.  168.    H.=3.    Emerald  green,  streak 
paler. 


E.    FUSIBLE  ;   ASSAY  ALKALINE  AFTER  IGNITION. 

WITHERITE,  p.  221.    H.=3-3'75  ;  G.  =4  29-4 "35  ;  trimetric  ;  white, 

ywh,  gyh  ;  B.B.  fuses  easily,  flame  ywh  green  ;  anhydrous. 
STRONTIANITE,  p.  223    H.=3'5-4  ;  G.  =3  6-3 '72  ;  trimetric  ;  pale 

green,    gray,    ywh,  white  ;    B.B.  fuses   only  on  thin   edges,  flame 

bright  red  ;  anhydrous. 
BARYTOCALCITE,  p.  222.    Monoclinic.  G.=3'6  3 '66  ;  B.B.  nearly 

like  witherite. 

Other  carbonates  are  the  Lead  Carbonate,  p.  152,  and  Copper  Car- 
bonates, p.  140,  included  severally  under  the  heads  of  LEAD  and  COP- 
PER, on  page  391. 


DETERMINATION    OF    MINERALS.  399 

B.  SULPHATES  or  SULPHIDES :  Reaction  for  Sulphur 
with  Soda. 

A.    FUSIBLE  ;   ASSAY  ALKALINE  AFTER  FUSION. 

BARITE,  p.  220.  H.=2'5-3'5  ;  G.=43  4'72  ;  trimetric  ;  white,  ywh, 
gyh,  bluish,  brown;  B.B.  decrepitates  and  fuses ;  flame  yellow- 
ish-green ;  anhydrous. 

CELESTITB,  p.  222.  H.=3-3'5;  G.=3'9-3'98;  trimetric;  white, 
pale  blue,  rdh  ;  B.B.  fuses  ;  flame  red  ;  anhydrous. 

ANHYDRITE,  p.  211.  H.=3-35;  G.=2D-30;  trimetric,  with 
three  rectangular  and  easy  cleavages  differing  but  slightly  ;  white, 
bluish,  gyh,  rdh,  red  ;  B.B.  fuses,  flame  reddish -yellow. 

GYPSUM,  p.  210.  H.  =1-5-2;  G.=2'3-235;  monoclinic,  one  per- 
feet,  pearly  cleavage  ;  white,  gray,  but  also  brown,  black  from  im- 
purities ;  B.B.  yields  much  water,  becomes  white  and  crumbles 
easily. 

B.   FUSIBLE  J    REACTION  FOR  IRON. 

COPIAPITE,  p.  182.   H.=15;  G.  =2 '14;  yellow  ;  on  coal,  becomes 
magnetic ;  hydrous. 
Hauynite,  p.  270,  also  gives  the  sulphur  reaction  with  soda. 


C.    INFUSIBLE,  OR  NEARLY  SO. 

ALUMINITE,  p.  199.     H.— 1-2  ;  G.  — 1'66  ;  adheres  to  the  tongue  ; 

white  ;    B.B.  blue  with  cobalt  solution.     Alunite,  p.  198,  is  similar, 

but  H.=4,  and  G. =2  "58-2  75. 
SPHALERITE,  p.  154.     H.^3'5-4  ;   G.  =3 "9-4 '2  ;  isometric  ;  light 

to  dark  resin -yellow  ;  B.  B.  on  coal,  coating  of  zinc  oxide. 


G.  AESENATE9  :  Arsenical  fumes  on  coal. 

SOORODITE,  p.  185.  H.r=3'5  4  ;  G.  =3- 1-3  3  ;  trimetric  ;  leek-green 

to  liver-brown  ;  B.B.  fuses  easily,  flame  blue,  and  with  soda  gives 

a  magnetic  bead  ;  on  coal  alliaceous  fumes  ;  in  H  Cl.  sol. 
PHARMACOSIDERITE,  p.  185.     H.=25;   G.=:29-3;   cubes  and 

tetrahedrons  ;   dark  green,  bnh,  reddish  ;   B.B.  same  as  for  scoro- 

dite. 
PHARMACOLITE,  p.  214.   H.^2-2'5  ;  G.  =2  6-2  75  ;  wh,  gyh,  rdh  ; 

monoclinic  with  one  eminent  cleavage  ;    B.B.   fuses,  flame   blue  ; 

on  coal,  alliaceous  fumes  ;    after  ignition  assay  alkaline  ;    in  HC1 

sol. 


400  DETERMINATION    OF   MINERALS. 

D.  SILICATES,  PHOSPHATES,  OXIDES  :  SPECIES  NOT  IN- 
CLTJDED  IN  THE  THREE  PRECEDING  SUBDIVISIONS. 

I.  Streak  deep  red,  yellow,  brownish-yellow,  green  or  black. 

A.  INFUSIBLE,  OR  FUSIBLE  WITH  MUCH  DIFFICULTY. 

HEMATITE,  p.  176.  Red  to  black  ;  streak  red  ;  B.B.  reaction  for 
iron  ;  magnetic  after  ignition  in  R.  F.  ;  anhydrous. 

LIMONITE,  p.  181.  Brownish  and  ochre-yellow  to  black  ;  streak 
brownish -yellow  ;  B.B.  gives  off  water,  turns  red,  becomes  mag- 
netic in  R.F. 

TURGITE,  p.  182.  Brown  to  black  ;  streak  red  ;  B.B.  gives  off 
water  ;  decrepitates  ;  becomes  magnetic  in  R.F. 

FERGUSONITE,  p.  202.     Brownish  black  ;  infusible. 

ZINCITE,  p.  155.  Red  ;  streak  orange  ;  B.B.  on  coal,  zinc  oxide 
coating,  and  coating  moistened  with  cobalt  solution,  green  in  R.F. 

B.  FUSIBLE  WITHOUT  MUCH  DIFFICULTY. 

WOLFRAMITE,  p.  183.  Grayish  to  brownish  black  ;  streak  dark 
reddish  brown  to  black;  lustre  submetallic  ;  G.  —1- 1-7  55.  B.B. 
fuses  easily,  and  becomes  magnetic  ;  reaction  for  tungsten. 

VIVIANITB,  p.  184.  Blue  to  green  (to  white)  ;  streak  bluish- 
white  ;  G.  =2-5-2 '7  ;  H.  =15-2,  hydrous  ;  B.B.  fuses  easily  to  mag- 
netic globule,  coloring  flame  bluish-green. 

TORBERNITE,  p.  170.  Bright  green,  square  tabular  micaceous 
crystals  ;  streak  paler  green  ;  H.=2-2'5  ;  hydrous  ;  yields  a  globule 
of  copper  with  soda. 

SAMARSKITE,  p.  202.  H.=5"5-6;  G.=56-58;  velvet-black; 
streak  dark  reddish  brown  ;  B.B.  fuses  on  the  edges. 

II.  Streak  grayish  or  not  colored. 

1.  INFUSIBLE. 

A.    GELATINIZE   WITH  ACID,  FORMING  A  STIFF  JELLY. 

CHRYSOLITE,  p.  255.  Yellow-green  to  olive -green,  looking  like 
glass;  H.=67;  G.=3'3-35;  B.B.  reacts  for  iron,  becomes  mag- 
netic ;  anhydrous. 

CHONDRODITE,  p.  281.  H.=6-65;  G.  =3 '1-3 "25  ;  pale  yellow 
to  brown,  and  reddish -brown  ;  lustre  vitreous  to  resinous  ;  B.B.  re- 
action for  iron  and  fluorine  ;  anhydrous. 

ALLOPHANE,  p.  296.  H.=3;  G.=1'8-1'9  ;  always  amorphous, 
never  granular  in  texture;  bluish,  greenish  ;  B.B.  infus.,  a  blue 
color  with  cobalt  solution  ;  hydrous. 

WiUemite,  Calamine,  Sepiolite,  fuse  with  great  difficulty,  and  are  in- 
cluded under  fusible  gelatinizing  species,  p.  402. 


DETERMINATION   OF   MINERALS.  401 

B.    NOT  FORMING  A  STIFF  JELLY  WITH  ACID  ;  HYDROUS. 

#.  Blue  with  cobalt  solution  (owing  to  presence  of  aluminum). 

WAVELLITE,  p.  201.  H.=3'25-4;  G.=2'3-2-4;  white  to  green, 
brown  ;  B.B.  bluish-green  flame  after  moistening  with  sulph.  acid. 

LAZULITE,  p.  199.  H.=5'6;  G.=3  3'1  ;  blue;  B.B.  green  flame, 
especially  after  moistening  with  sulph.  acid  ;  hydrous. 

TURQUOIS,  p.  200.  H.=6  ;  G.  =2-0-285;  sky-blue,  pale  green; 
B.B.  flame  green. 

KAOLINITE,  p.  310.  H.=l-2;  G.  =2 '4-2  65;  white  when  pure; 
feel  greasy  ;  B.B.  flame  not  green. 

GIBBSITE,  p.  194.  H.=2'5-3'5  ;  G.=2'3-2'4  ;  white,  grayish,  green- 
ish ;  B.B.  flame  not  green  ;  soluble  in  strong  sulph.  acid. 

DIASPORE,  p.  194.  H.  =6-5-7  ;  G.  =3'3-3'5  ;  in  thin  foliated  crys- 
tals, plates  or  scales;  white,  greenish,  brownish  ;  B.B.  flame  not 
green  ;  soluble  in  sulphuric  acid  after  ignition. 

b.  Pale  red  or  pink  color,  with  cobalt  solution  (owing  to  presence  of 
magnesium). 

BRUCITE,  p.  204.  H.=2'5;  G.=2'3-245  ;  pearly,  white,  green- 
ish ;  foliaceous  or  fibrous  and  flexible  ;  B.B.  after  ignition,  alkaline. 

c.  Not  blue  or  red  with  cobalt  solution. 

OPAL,   p.  239.     H.  =5-5-6-5;   G.=l-9-2'3;    B.B.  with  soda  soluble 

with  effervescence. 
GENTHITE,   p.    309.     H.=3-4;    G.=2'4;    pale  green,  yellowish; 

B.B.  with  borax  a   violet  bead,  becoming  gray  in  R.F.  owing  to 

nickel  ;  decomp.  by  H  Cl. 
CHRYSOCOLLA,  p.  142.     H.=2-4  ;  G.=2  2'24  ;  pale  bluish-green 

to  sky-blue  ;  B.B.  flame  emerald-green,  and  with  soda  on  coal  globule 

of  copper. 

The  micas,  chlorites,  chloritoid,  and  serpentine  often  fuse  on  their 
edges  with  much  difficulty. 

C.    NOT  FORMING  A   STIFF  JELLY  ;  ANHYDROUS.      H.=5  to  9. 
a.  Blue  color  with  cobalt  solution. 

CORUNDUM,  p.  192.  H.=9;  G.=4;  rhombohedral ;  blue,  white, 

red,  gray,  brown. 

CHRYSOBERYL,  p.  196.     H.=8'5  ;  G.=3'7  ;  gray,  green,  to  eme- 
rald-green. 
TOPAZ,   p.  286.     H.=8;  G.=3'5;  in  rhombic  prisms  with  perfect 

basal   cleavage,  rarely   columnar ;   white,    wine-yellow,  and  other 

shades. 
RUBELLITE,  p.  283.  H.=7'5  ;  G.=3  ;  in  prisms  of  3,  6,  or  9  sides  ; 

rose-red  ;  reaction  for  boron. 
ANDALUSITE,   p.    284.      H.=7'5;   G.=3'2;  always  in  prismatic 

crystals,  often  tesselated  within,  /A 7=93°  ;  grayish-white  to  brown. 
FIBROLITE,  p.  285.     H.=6-7  ;  G.=3'2  ;  columnar  or  fibrous  forms 

and  prismatic  crystals  with  brilliant  diag.  cleavage. 


402  DETERMINATION    OF   MINERALS. 

CYANITE,   p.  286.     H.— 5-7  (greatest  on  extremities  of  crystals); 

G.  — 3'6  ;  in  long  or  short  prismatic  crystallizations,  often  bladed 

prisms  ;  pale  blue  to  white  and  gray. 
LEUCITE,  p.  271.  H.  =5'5-6  ;  G.  =2'5  ;  white,  gyh  ;  often  in  trapezo- 

hedral  crystals. 

&.  Not  giving  a  blue  or  reddish  color  with  cobalt  solution  ;  H.  = 

8  to  5. 

SPINEL,  p.  194.  H.=8  ;  G.  =3'5  4'1  ;  in  octahedrons  of  red,  green- 
ish, gray,  black  colors.  Gahnite  is  similar,  but  with  borax  on  coal, 
gives  reaction  for  zinc. 

BERYL,  p.  252.  H.=7'5-8;  G.=2'6-2'7;  always  in  hexagonal 
prisms  ;  pale  bluish  and  yellowish  green,  to  emerald-green,  also 
resin  yellow  and  white,  no  distinct  cleavage. 

ZIRCON,  p.  259.  H.=7-5  ;  G.  =4-4*75  ;  dimetric,  and  often  in  square 
prisms  ;  lustre  adamantine  ;  brown,  gray. 

STAUROLITE,  p.  291.  H.=7;  G.=3'4-3'8;  in  prisms  of  123°, 
and  often  in  cruciform  twins  ;  no  distinct  cleavage  ;  brown,  black, 
gray. 

QUARTZ,  p.  233.  H.=7;  G.=2'6;  often  in  hexagonal  crystals 
with  pyramidal  terminations ;  of  various  shades  of  color.  OPAL, 
p.  239,  is  in  part  anhydrous. 

MONAZITE,  p.  203.  H.=5-5'5;  G.=4'9-5'3;  in  small  brown  im- 
bedded monoclinic  crystals,  with  perfect  basal  cleavage  ;  B.B.  flame 
bluish-green  when  moistened  with  sulph.  acid. 

RUTILE,  p.  162.  H.=6-65;  G.=4'15-4'25  ;  dimetric;  reddish- 
brown  to  brownish -red,  green,  black  ;  B.B.  reaction  for  titanium. 
BROOKITE  and  OCTAHEDRITE,  p.  163,  are  similar,  except  in  crystal- 
line forms,  and  G.  in  brookite  4'0-4'2o,  in  octahedrite  3'8-3'95. 

PEROFSKITE,  p.  163.  H.=5-5  ;  G.^4-4'1;  yellowish,  brown, 
black  ;  cubic  and  octahedral  forms  ;  B.B.  reaction  for  titanic  acid. 

ENSTATITE,  p.  244.  H.=5'5  ;  G.=3'l-3'3  ;  in  prismatic  and  fibrous 
forms  with  /A/=88D  16',  also  foliated  ;  whitish,  grayish,  brown. 
Anthophyllite  is  similar,  but  /A 7=125%  and  it  fuses  on  the  edges 
with  great  difficulty. 

lolite,   apatite,   scheelite,   eudase,   fuse  with  much  difficulty,   and 
euclase  gives  some  water  in  closed  tube  when  highly  ignited. 


2.  FUSIBLE  WITH  LITTLE  OR  MUCH  DIFFICULTY. 
A.  Gelatinize  and  afford  a  Stiff  Jelly, 

a.  Hydrous ;  fuse  easily. 

DATpLITE,  p.  289.  H.=5-5'5;  G.=2'8-3;  white,  greenish,  yel- 
lowish ;  crystals  glassy,  stout,  sometimes  massive  and  porcellanous, 
never  fibrous  ;  B.B.  fuses  easily,  reaction  for  boron. 

NATROLITE,  p.  299.  H.=5-5'5  ;  G.=2'3-2  4  ;  in  slender  rhombic 
prisms,  and  divergent  columnar  ;  white,  y  wh,  rdh,  red  ;  B.B.  fuses 
very  easily. 

SCOLECITE,  p.  299.     H.=5-5'5  ;  G.=216-2'4;  cryst.  much  like 


DETERMINATION    OF   MINERALS.  403 

natrolite,  but  twinned,  with  converging  striae  on  i-i  as  in  figure  on 

p.  299;  B.B.  sometimes  curls  up,  fuses  very  easily. 
GMELINITE,  p.  301.     H.  =4'5  ;  G.  =2-22  ;  in  small  and  short  hex- 

agonal  or  rhombohedral  cryst.  ;  B.B.  fuses  easily. 
PHILIPPS1TE,   p.   302.     H.=4-4'5  ;   G.  =2 "2  ;  in  twinned  crystals  ; 

B.B.  fuses  rather  easily. 
LAUMONTITE,   p.    293.    H.=3'5-4  ;  G.=2'2-2'4  ;    white,  reddish; 

crystals   become  white  and  crumbling  on  exposure  to  the  air ;  B.B. 

fuses  rather  easily. 

Pectolite  (p.  293),  and  Analdte  (p.  299),  imperfectly  gelatinize. 

&.  Hydrous  j  fuse  with  much  difficulty. 

CALAMINE,  p.  157.  H.=4'5-5  ;  G.=3  15-319  ;  white,  greenish, 
bluish  ;  orthorhombic  in  crystals ;  B.B  fus.  with  great  difficulty,  re- 
action for  zinc  and  none  for  iron  ;  hydrous. 

SEPIOLITE,  p.  306.  White  ;  soft  and  almost  clay-like,  also  fibrous  ; 
B.B.  fuses  with  difficulty,  with  cobalt  solution  reddish  ;  hydrous. 

PYROSCLERITE,  p.  317.  H.=3  ;  G.=2'74;  micaceous  ;  B.B.  fuses 
on  thin  edges. 

c.  Anhydrous. 
a    NO  REACTION  FOR  SULPHUR  ;  NO   COATING  ON  COAL. 

NEPHELITE,  p.  269.   H.=5'5-6  ;  G.=2'5-2"65  ;    hexagonal  prisms 

and  massive  ;  vitreous,  with  greasy  lustre  ;  white,  y  wh,  gyh  brown, 

rdh  ;  B.B.  fuses  rather  easily. 
WOLLASTONITE,   p.   244.     H  =4'5-5  ;  G.  =2 "75-2 "9  ;  white,  gyh, 

rdh,  bnh  ;  B.B.  fuses  easily. 
SODALITE,   p.    270.      H.=5'5-6;  G.=2'13-2-4;    white,  blue,  red- 

dish  ;  in  dodecahedrons  and  massive  ;  B.B.  fuses  not  very  easily. 
WILLEMITE,  p.  157.      H.=5'5;   G.=3'9-43;  white  to  greenish, 

reddish,  brownish  ;    B.B.  glows  and  fuses  with  difficulty  ;   reaction 

for  zinc  and  none  for  iron  ;  anhydrous. 

ft.  REACTION  FOR  SULPHUR  B.B.  WITH  SODA. 

HAUYNITE,  p.  270.  H.=5'5-6  ;  G.=2'4-25  ;  blue,  greenish;  iso- 
metric, in  dodecahedrons,  octahedrons ;  B.B.  fuses  with  some  diffi- 
culty. 

DANALITE,  p.  256.  H.  =5 "5-6  ;  G.  =3-427  ;  isometric  ;  flesh-red  to 
gray  ;  B.B.  fuses  rather  easily,  and  gives  reaction  for  manganese 
and  zinc. 

B.  Not  Gelatinizing. 

STRUCTURE  EMINENTLY  MICACEOUS,  SURFACE  OF  FOLIA 
MORE  OR  LESS  PEARLY  ;   H.  OF  SURFACE  OF  FOLIA 
NOT  OVER  3'5;  ANHYDROUS  OR  HYDROUS. 

FSCOVITE,  BIOTITE,  PHLOGOPITE,  LEPIDOLITE,  LE. 

PIDOMELANE  :   for  distinctions  see  pp.  266-268.     Anhydrous, 


404  DETERMINATION   OF    MINERALS. 

or  affording  very  little  water;  B.B.  fuse  with  difficulty  on  thin 
edges,  excepting  lepidomelane  which  fuses  rather  more  easily. 

MAKGARODITE,  DAMOURITE,  p.  313.  Much  like  common 
mica,  but  more  pearly  and  greasy  to  the  feel,  folia  not  elastic  ;  giv- 
ing a  little  water  in  the  closed  tube  ;  color  usually  whitish. 

PENNINITE,  RIPIDOLITE,  PROCHLORITE,  p.  318.  Usually 
bright  or  deep  green,  blackish-green,  reddish,  rarely  white  ;  folia 
tough,  inelastic;  B.B.  diff.  fus.,  reaction  for  iron  and  yield  much 
water  ;  partially  decomposed  by  acids. 

VERMICULITE,  JEFFERISITE,p.  317.  Brown,  yellowish-brown, 
green  ;  exfoliate  remarkably  ;  yield  much  water. 

MARGARITE,  p.  319.  H.-8;5-4'5  (highest  on  edges);  G.=2-99; 
white,  ywh,  rdh  ;  folia  somewhat  brittle  ;  B.B.  fuses  on  thin  edges  ; 
yields  a  little  water. 

TALC,  p.   304. 


FYROPHYLLITE,   p.    306.     Similar  to  talc;   but  B.B.  exfoliates 

remarkably  ;  blue  with  cobalt  solution. 
FAHLUNITE,  p.  314,  has  often  a  more  or  less  distinct  micaceous 

structure. 

Autunite,  p.  170,  has  a  mica-like  basal  cleavage  ;  but  it  occurs 
in  small  square  tables  of  a  bright  yellow  color.  Diallage,  p.  246, 
has  a  structure  nearly  micaceous.  Serpentine  is  sometimes  nearly 
micaceous,  but  the  folia  are  not  easily  separable  and  are  brittle. 
Chloritoid  has  a  perfect  basal  cleavage,  but  folia  very  brittle,  and 
cleavage  less  easily  obtained  than  in  the  preceding ;  and  moreover  the 
mineral  is  infusible. 

2.  STRUCTURE  NOT  MICACEOUS. 
a.  Hydrous. 

a.   NO  REACTION  FOR  PHOSPHORUS,  OR  BORON. 

t  Hardness,  with,  the  exception  of  a   variety  of  serpentine,  1  to  3  ? 
lustre  not  at  all  vitreous, 

CHLORITES,  p.  318.  H.=2-25.  Here  fall  the  massive  granular 
chlorites,  olive-green  to  black  in  color,  of  the  species  penninite,  ri- 
pidolite,  prochlorite;  B.B.  reaction  for  iron,  fuses  with  difficulty; 
yields  much  water. 

VERMICULITE,  p.  317.  H.=1-1'5.  Granular  massive  forms  of 
vermiculite. 

TALC,  p.  304.  H.=1-1'5.  Here  falls  steatite  (soapstone)  or  massive 
talc,  of  white  to  grayish  green  and  dark  green  color,  granular  to 
cryptocrystalline  in  texture.  B.B.  fuses  with  great  difficulty,  and 
yields  only  traces  of  water  ;  no  reaction  for  iron,  or  only  slight. 

PYROPHYLLITE,  p.  306.  Grayish  white,  massive  or  slaty  ;  B.B. 
like  the  crystallized,  p.  403,  in  its  difficult  fusibility  and  little  water 
yielded,  but  does  not  exfoliate. 

SERPENTINE,  p.  307.  H.=2'5-4;  G.  =2 "36-2 '55  ;  olive-green; 
ywh  green  ;  blackish  green,  white  ;  B.B.  fuses  with  difficulty  on 
thin  edges  ;  yields  much  water. 


DETERMINATION    OF   MINERALS.  405 

FINITE,  p.  312.  H.=2-5-3'5;  G.^2-6-2'85 ;  lustre  feebly  waxy; 
gray,  gnh,  bnh.  B.B.  fuses;  yields  water. 

DAMOURITE,  p.  313.  Same  as  crystallized,  p.  403,  but  in  mas- 
sive aggregation  of  scales. 

tt  Hardness  3-5  to  6'5  ;    lustre  often  pearly  on  a  cleavage  surface, 
but  elsewhere  vitreous. 

PREHNITE,  p.  295.  H.=6-6'5;  G.=2'8-3;  pale  green  to  white; 
crystals  often  barrel -shaped,  made  of  grouped  tables  ;  B.B.  fuses 
very  easily  ;  decomp.  by  H  Cl. 

PECTOLITE,  p.  293.  K.=5  ;  G.=2'68-2  8  ;  white  ;  divergent  fibrous, 
or  acicular;  B.B.  fuses  very  easily;  gelatinizes  imperfectly  with 
HC1. 

APOPHYLLITE,  p.  294.  H.=4'5-5  ;  G.=2  3-2'4  ;  white,  gnh,  ywh, 
rdh  ;  dimetric,  one  perfect  pearly  cleavage  transverse  to  prism ; 
B.  B.  fuses  very  easily  ;  a  fluorine  reaction  ;  decomp.  by  H  Cl. 

OHABAZITE,  p.  300.  H.=4-5  ;  G.=2-2  2  ;  rhombohedral,  vitreous; 
white,  rdh  ;  B.  B.  fuses  easily  ;  decomp.  by  H  Cl. 

HARMOTOME,  p.  301.  H.=4'5;  G.=2'44;  white,  ywh,  rdh; 
crystals  twins,  usually  cruciform  ;  B.B.  fuses  not  very  easily ;  vitre- 
ous in  lustre  ;  decomp.  by  H  Cl. 

STILBITE,  p.  302.  H.=3'5-4  ;  G.=2-2  2  ;  white,  ywh,  red  ;  crys- 
tallizations often  radiated-lamellar ;  one  perfect  pearly  cleavage ; 
B.  B.  exfoliates,  fuses  easily  ;  decomp.  by  H  Cl. 

HEULANDITE,  p.  303.  H.=35-4;  G.=22;  in  oblique  crystals, 
with  one  perfect  pearly  cleavage  ;  B.B.  same  as  for  stilbite. 

EUCLASE,  p.  288.     H.  =7-5  ;  G.  =81  :  in  glassy  transparent  mono- 
clinic  crystals;    B.B.   fuses  with  great  difficulty ;   gives  water  in 
closed  tube  when  strongly  ignited. 
Prehnite,  apopliyllite,  chabazite,  harmotome,  heulandite,  and  enclose 

never  occur  in  fibrous  forms. 

ft.  REACTION  EITHER  FOR  PHOSPHORUS  OR  BORON. 

VIVIANITE,  p.  184.  H.=15-2;  G.=2'55-7;  monoclinic  with  one 
perfect  cleavage  ;  white,  blue,  green ;  B.B.  fuses  very  easily,  the 
flame  bluish  green,  a  gray  magnetic  globule  ;  in  H  Cl  sol. 

ULEXITE,  p.  212.  H.=l;  G.  =1 -65  ;  white,  silky,  in  fine  fibres  ; 
B.B.  fuses  very  easily,  and  moistened  with  sulph.  acid  flame  for  an 
instant  green,  "owing  to  the  boron  present ;  little  sol.  in  hot  water. 
PRICEITE  (p.  212)  is  in  texture  and  color  like  chalk ;  similar  to 
ulexite  in  green  flame  B.B. 
Borax  and  Sassolite  are  other  soft  minerals  containing  boron,  but 

these  have  taste. 

I.  Anhydrous. 

a.   B.B.  the  flame  lithium-red. 

SPODUMENE,  p.  248.  H.=6'5-7;  G.=813-8'19;  white,  gyh,  gnh 
white,  monoclinic  (like  pyroxene),  with  /A 7=87°,  and  perfect 
cleavage  parallel  to  7 and  i-i;  B.B.  swells  and  fuses. 


406  DETERMINATION  OF   MINERALS. 

PETALITE,  p.  248.  H.=6-6'5;  G.=2-4-2'5;  white,  gray,  rdh, 
gnh  ;  B.B.  becomes  glassy  and  fuses  only  on  the  edges. 

HEBRONITE,  AMBIiYGONITE,  p.  199.  H.  =6  ;  G.  =3-31  ;  moun- 
tain green,  gyh,  white,  bnh  ;  B.B.  fuses  very  easily,  reaction  for 
fluorine. 

TRIPHYLITE,  p.  190.  H.=5  ;  G.=3'5-3'6  ;  greenish  gray,  bluish, 
often  bnh  black  externally  ;  B.B.  fuses  very  easily,  globule  mag- 
netic ;  with  soda,  manganese  reaction. 

LEPIDOLITE,  p.  268.  H.=2  5-4  ;  G.=2'8-3  ;  micaceous,  also  scaly- 
granular;  rose-red,  pale  violet,  white,  gyh;  B.B.  fuses  easily; 
after  fusion  gelat.  with  H  Cl.  Some  Uotite,  p.  266,  gives  the  lithia 
reaction. 

(3 .  B.B.  boron  reaction  (green  flame). 

TOURMALINE,  p.  282.  H.=7  ;  G.=2  9-3'3  ;  rhombohedral,  prisms 
with  3,  6,  9  sides,  no  longitudinal  or  other  distinct  cleavage  ;  black, 
blue  black,  green,  red,  rarely  white  ;  lustre  of  dark  var.  resinous  ; 
B.B.  fusion  easy  for  dark  var.  and  diff.  for  light. 

AXINITE,  p.  264.  H.  =6*5-7  ;  G.=3  27  ;  triclinic,  sharp-edged,  glassy 
crystals  ;  rich  brown  to  pale  brown  and  grayish  ;  B.B.  fuses  readily  ; 
with  borax  violet  bead. 

BORACITE,  p.  206.  H.=7  ;  G.=2'97  ;  isometric  ;  white,  gyh,  gnh  ; 
lustre  vitreous  ;  fuses  easily,  coloring  flame  green. 

Dariburite,  p.  264,  is  another  boron  silicate. 

y.  B.B.  reaction  for  titanium. 

TTTANTTE,  p.  290.  H.=5-5'5  ;  G.=3'4-3'56  ;  monoclinic  ;  usually 
in  thin  sharp-edged  crystals  ;  brown,  ywh,  pale  green,  black  ; 
lustre  usually  subresinous  ;  B.B.  fuses  with  intumescence. 

3.  Reaction  for  fluorine  or  phosphorus. 

CRYOLITE,  p.  197.  H.=2'5  ;  G.=2'9-3  ;  white,  rdh,  bnh  ;  fuses  in 
the  flame  of  a  candle  ;  soluble  in  sulph.  acid  which  drives  off  hydro- 
gen fluoride,  a  gas  that  corrodes  glass. 

FLUORITE,  p.  208.  H.=4;  G.=3-3'25;  isometric,  with  perfect 
octahedral  cleavage,  and  massive  ;  white,  wine-yellow,  green,  pur- 
ple, rose-red,  and  other  bright  tints  ;  phosphoresces  ;  when  heated, 
decrepitates  ;  B.B.  fuses,  coloring  the  flame  red  ;  after  ignition, 
alkaline. 

Lepidolite  (p.  268),  Amblygonite  (p.  199),    also  give  a  fluorine  re- 
action. 

APATITE,  p.  212.  H.=4'5-5  ;  G.  =2 '9-3 '25  ;  often  in  hexagonal 
prisms  ;  pale  green,  bluish,  yellow,  rdh,  bnh,  pale  violet,  white  ; 
B.B.  fuses  with  difficulty,  moistened  with  sulph.  acid  and  heated, 
flame  bluish  green  from  presence  of  phosphorus  ;  sometimes  reaction 
for  fluorine. 

S.  Reaction  for  iron. 

GARNET,  p.  256.  H.  =6 "5-7 "5  ;  G.=3'15-4'3  ;  isometric,  usually  in 
dodecahedrons  and  trapezohedrons,  also  massive,  never  fibrous  or 
columnar  ;  red,  bnh  red,  black,  cinnamon  red,  pale  green,  to  emerald- 


DETERMINATION   OP   MINERALS.  407 

green,  white.  B.B.  dark-colored  varieties  fuse  easily,  and  give  iron 
reaction,  but  emerald-green  var.  almost  infusible  ;  a  white  to  yellow 
massive  garnet  is  hardly  determinable  without  chemical  analysis. 

VESUVIANITE  (Idocrase),  p.  261.  H.-6'5  ;  G.  =3*35-3-45  ;  dimetric 
and  often  in  prisms  of  four  or  eight  sides,  never  fibrous  ;  brown  to 
pale  green,  ywh,  bk  ;  B.B.  fuses  more  easily  than  garnet ;  reaction 
for  iron. 

EPIDOTE,  p.  262.  H.=6-7;  G.=3'25-3'5;  in  monoclinic  cryst. 
and  massive,  .rarely  fibrous  ;  unlike  amphibole  in  having  but  one 
cleavage  direction  ;  ywh  green,  bnh  green,  black,  rdh,  yellow,  dark 
gray  ;  B.B.  fuses  with  intumescence. 

AMPHIBOLE,  dark  varieties  including  Jwrriblende,  actinolite,  and 
other  green  to  gray  and  black  kinds,  p.  249.  H.--=5'6  ;  G.=3-3'4  ; 
monoclinic,  in  short  or  long  prisms,  often  long  fibrous,  lamellar,  and 
massive,  prisms  usually  four  or  six  sides,  /A/=124i°,  cleavage  par. 
to  1 ;  B.B.  fusion  easy  to  moderately  difficult. 

ANTHOPHYLLITE,  p.  252,  like  hornblende  ;  bnh  gray  to  bnh 
green,  sometimes  lustre  metalloidal ;  B.B.  fuses  with  great  diffi- 
culty. 

PYROXENE,   augite,    and    all    green    to    black   varieties,   p.    245. 

^  H.=5-6  ;  G.=r3'2-3'5  ;  monoclinic,  in  short  or  oblong  prisms,  lamel- 
lar, columnar,  not  often  long,  fibrous  or  asbestiform,  prisms  usually 
with  four  or  eight  sides,  /A 7=87°  5',  cleavage  par.  to  1 ;  B.B.  as 
in  hornblende. 

HYPERSTHENE,  p.  244.  H.=5-6;  G.=3'39;  cryst.  nearly  as  in 
pyroxene,  but  trimetric,  usually  foliated  massive,  also  fibrous  ;  bnh 
green,  gyh  black,  pinchbeck-brown  ;  B.B.  fuses  with  more  or  Jess 
difficulty.  Bronzite,  p.  244,  is  similar  and  almost  infusible. 

IOLITE,  p.  264.  H.=7-7'5  ;  G.  =2 "6-2  7  ;  blue  to  blue  violet ;  looks 
like  violet-blue  glass  ;  B.B.  fuses  with  much  difficulty. 

Tourmaline,  much  Titanite,  and  lhaite  (p.  263),  B.B.  give  iron  re- 
action. 

C.  No  reaction  for  iron. 

SCHEELITE,  p.  212.  H.=4'5-5  ;  G.:=5-9-6-l ;  ywh,  gnh,  rdh,  pale 
yellow  ;  lustre  vitreous-adamantine  ;  fuses  on  the  edges  with  great 
difficulty. 

SCAPOLITES,  p.  268.  H.=5'5-6;  G.=2'6-2'74;  dimetric,  often 
in  square  prisms  ;  white,  gray,  gnh  gray  ;  B.B.  fuses  easily  with  in- 
tumescence. 

ZOISITE.  p.  263.  H=6-6'5;  G.— 3'l-3'4;  trimetric,  oblong  prisms 
and  lamellar  massive,  cleavage  in  only  one  direction. 

AMPHIBOLE,  white  var.  (tremolite),  p.  249.  Same  as  for  other 
amphibole  (above),  except  in  color  ;  B.B.  fuses. 

PYROXENE,  white  var.,  p.  215.  Same  as  for  other  pyroxene  (above), 
except  in  color  ;  B.B.  fuses. 

ORTHOCLASE,  p.  278.  H.=6-6'5  ;  G.=2'4^2'62  ;  monoclinic,  stout 
cryst.,  and  massive,  never  columnar,  two  unequal  cleavages,  the 
planes  at  right  angles  with  one  another,  and  cleavage  surfaces  never 
finely  striated,  as  seen  under  a  pocket  lens  or  microscope  ;  white, 
gray,  flesh-red,  bluish,  green  ;  B.B.  fuses  with  some  difficulty. 


408  DETERMINATION   OF   MINERALS. 

ALBITE,  p.  277,  OLIGOCLASE,  p.  276.  H.=6;  G.=256-2'72; 
triclinic,  but  cryst.  as  in  orthoclase,  except  that  the  two  cleavage 
planes  make  an  angle  of  93i°  to  94°,  and  one  of  them  has  the  surface 
striated  ;  white  usually,  flesh-red,  bluish  ;  B.B.  fuse  with  a  little 
difficulty  ;  not  acted  on  by  acids. 

LABRADORITE,  p.  276.  H.=:6  ;  G.=2'66-2'76 ;  triclinic,  like  albite 
in  cryst.,  and  nearly  in  cleavage  angle,  93°  20',  and  in  striae  of 
surface  ;  white,  flesh -red,  bnh  red,  dark  gray,  gyh  brown ;  B.B. 
fuses  easily  ;  decomposed  by  HC1  with  difficulty. 

ANORTHITE,  p.  275.  H  =6-7  ;  G.=2'66-2'78  ;  cryst,  and  stria? 
as  in  albite,  cleavage  angle  94°  10'  ;  white,  gyh,  rdh  ;  B.B.  fusion 
difficult ;  decomposed  by  HC1  with  separation  of  gelat.  silica. 

MICROCLINE,  p.  278.  Very  near  orthoclase  in  all  characters,  but 
triclinic,  cleavage  angle  differing  only  16'  from  a  right  angle,  and 
surface  of  most  perfect  cleavage  striated,  but  striae  exceedingly 
fine,  often  difficult  to  detect  with  a  good  pocket  lens,  and  requiring 
the  aid  of  a  polariscope  ;  color  white,  gray,  flesh-red,  often  green. 
For  optical  distinctions  of  FELDSPARS,  see  p.  274. 

EUCLASE,  p.  288.  H.  =7'5;  G.=8'l  ;  in  monoclinic  crystals,  with 
one  perfect  diagonal  cleavage ;  pale  green,  to  white,  bnh  ;  trans- 
parent ;  becomes  electric  by  friction. 


ON  ROCKS. 

I.   CONSTITUENTS  OF  EOCKS. 

ROCKS  are  made  up  of  minerals.  A  few  kinds  consist  of 
a  single  mineral  alone  :  as,  for  example,  limestone,  which 
may  be  either  the  species  calcite  or  dolomite  ;  quartzyte 
(along  with  much  sandstone),  which  is  quartz  ;  WDAfelsyfet 
which  is  orthoclase.  But  even  these  simple  kinds  are  sel- 
dom free  from  other  ingredients,  and  often  contain  visibly 
other  minerals.  Nearly  all  kinds  of  rocks  are  combinations 
of  two  or  more  minerals.  They  are  not  definite  compounds, 
but  indefinite  mixtures,  and  hardly  less  indefinite  than  the 
mud  of  a  mud-flat.  The  limits  between  kinds  of  rocks 
are  consequently  ill-defined.  Granite  graduates  insensibly 
into  gneiss,  and  gneiss  as  insensibly  into  mica  schist  and 
quartzyte,  syenyte  into  granite,  mica  schist  into  hornblende 
schist,  granite  also  into  a  compact  porphyry-like  rock,  and 
trachyte;  and  so  it  is  with  many  other  kinds.  The  fact 
is  a  chief  source  of  the  difficulty  in  studying  and  defining 
rocks,  and  especially  the  crystalline  kinds.  The  different 
rocks  are  not  species  in  the  sense  in  which  this  word  is  used 
in  science,  but  only  kinds  of  rocks. 

The  minerals  which  are  the  chief  constituents  of  rocks 
are  of  two  classes  :  (A)  the  Siliceous;  (B)  the  Calcareous. 

A.  The  siliceous  are  as  follows  : 

1.  Quartz,  which  probably  makes  up  one-third   of  the 
rocky  material  of  the  crust  of  the  globe. 

2.  The   Feldspars  (p.  272)  ;  of   which   orthoclase   (with 
microcline)  is  most   abundant ;  next  to  it,  oligoclase  and 
labradorite  ;  and  next  alb  it e,  andesite,  and  anortMte. 

3.  The  Micas  (p.  205)  :  muscovite  and  biotite,  of  equal 
prominence,  the  others  much  less  common. 

4.  Ampliibole  and  Pyroxene  species  (p.  245,  and  beyond)  : 
especially  hornblende  or  black  amphibole,   and  augite  or 

409 


410  DESCRIPTIONS   OP   ROCKS. 

black  pyroxene  ;  also  the  green  hornblende  or  actinolite;  the 
green  foliated  hornblende  called  xmaragdite,  and  the  foli- 
ated pyroxene  sometimes  wrongly  called  hypersthene,  and 
another  variety  called  diallage;  also  occasionally  the  species 
Jiypersthene  and  cnstatite. 

5.  The  Felclspar-rlike  minerals,  nepJielite  (p.  269)  and  leu- 
cite  (p.  271),  which  are  related  in  constituents  and  quan- 
tivalent  ratios  to  the  feldspars,  alumina  being  the  only  ses- 
quioxide  base,  and  lime,  potash,  and  soda  the  protoxide  bases 
afforded  in  analyses  ;  the  atomic  ratios  for  the  protoxides, 
sesquioxide,  and  silica  being  in  nepheiite,  1  :  3  :  4,  as   in 
anorthite  ;  and  in  leucite  1  :  3  :  8,  as  in  andesite.    Also,  less 
abundantly,  Sodalite   (p.  270),   which  has   essentially  the 
ratio  of  anorthite  and  nephelite. 

6.  Minerals  of  the  Saussurite  group.     These  jade-like 
species  differ  from  the  feldspars — (1)  in  being  always  fine- 
grannlar  in   texture;    (2)  in  having  a  high  density,  G-. — 
#•9-3  '4  ;    in  varying  from   the   feldspar   type   chemically. 
They  are  near  some  soda-lime  feldspars  in  constituents,  but 
not  ahvays  in  the  atomic  relations  of  the  constituents,  nor 
in   the   absence   uniformly   of   magnesia.     There   are   two 
prominent  kinds.     One  is  between  anorthite  and  zoisite  in 
composition   (see  p.   263) ;  yet,  unlike  .these  minerals,   its 
analyses  afford  several  per  cent,  of  soda  and  some  magnesia. 
The  second  approaches  labradorite  ;  Delesse  obtained  for  a 
specimen  from  Mt.  Genevre  (Alps),  Silica  49 '73,   alumina 
29*65,  iron  protoxide  0*85,  magnesia  0*56,  lime  11*18,  soda 
4-04,  potash  0*24,   water  (with  a  little  C02)  3-75  ;  and  a 
Silesian  specimen  afforded  Vom  Rath  nearly  the  same  result. 
A  third  kind  from  Corsica,  according  to  Boulanger's  analy- 
sis, has  nearly  the  same  composition   as   zoisite.     A.  fourth 
is  jadeite  (p.  263),  a  stone  occurring  in  the  Swiss  lake-dwell- 
ings— but  not  yet  found  in  the  saussurite  rocks  of  Switzer- 
land. 

The  saussurite  of  Siberia  and  the  Alps  has  been  observed 
to  have  sometimes  the  form  of  twins  of  a  triclinic  feldspar. 
This,  and  the  texture,  density,  and  composition,  show  that 
saussurite  is,  in  part  at  least,  pseudomorphous,  and,  in  somo 
regions,  after  labradorite.  By  some  peculiar  conditions  in 
the  process  of  metamorphism — perhaps  long-continued  heat 
with  an  unusual  amount  of  moisture — the  feldspar  crystal- 
lizations that  formed  in  the  incipient  stages  of  the  process 
were  afterward  changed  to  a  species  of  higher  density  and 


DESCRIPTIONS   OP   ROCKS.  411 

different  molecular  nature  ;  in  other  words/to  saussurite. 
Some  of  the  material  appears  to  be  still  labradorite. 

7.  The  iron-bearing  minerals,  Epidote  (p.  262),  Garnet 
(p.  250),  Chrysolite  (p.  255),  which  characterize  some  varie- 
ties of  rocks. 

B.  The  calcareous  species  are  calcite  or  calcium  carbonate 
(p.  215),  in  various  states  of  impurity  ;  and  dolomite  or  cal- 
cium-magnesium carbonate  (p.  219),  which  in  its  rock-form 
is  undistinguishable  in  external  aspect  from  calcite. 

Gypsum,  or  hydrous  calcium  sulphate,  is  also  a  consti- 
tuent of  beds  among  rocks,  and  should  have  its  place  in  the 
list,  although  not  strictly  embraced  under  the  term  calca- 
reous. 

Of  the  siliceous  minerals,  orthoclase  (with  microcline), 
and  the  two  micas,  muscovite  and  biotite,  are  related  in  com- 
position, in  that  each  affords  10  per  cent,  or  more  of  pot- 
ash. Leucite  is  another  allied  potash-alumina  silicate,  even 
richer  in  potash  than  orthoclase,  it  containing  17  to  21  per 
cent.  The  rocks  characterized  by  these  minerals  are  hence 
rich  in  potash. 

Albite  and  oligoclase,  and  also  sodalite,  afford  much  soda, 
the  first  two  usually  8  to  12  per  cent. ,  and  sodalite,  20  to 
25  per  cent.  Nephelite  (elaeolite)  is  also  a  soda  mineral 
related  to  the  feldspars  ;  but,  with  15  to  16  per  cent,  of  soda, 
there  are  5  or  6  of  potash  ;  rarely  the  alkali  afforded  is  all 
soda. 

The  ordinary  kinds  of  hornblende  and  pyroxene,  on  the 
contrary,  afford  little  or  no  soda  or  potash.  They  thus  dif- 
fer widely  from  the  potash  and  soda  species  just  mentioned, 
and  naturally  characterize  for  the  most  part  a  distinct  series 
of  rocks. 

Much  importance  has  been  allowed  in  lithology  to  the 
distinction  of  foliated  under  the  species  hornblende  and 
pyroxene ;  when,  in  fact,  neither  in  mineralogy,  as  all 
treatises  admit,  nor  in  lithology,  has  it  more  than  a  very 
subordinate  value.  The  character  obtained  this  distinction 
before  it  was  fully  understood  that  the  foliated  forms  were 
identical  in  composition  with  those  in  crystals  or  in  massive 
forms. 

Hornblende  does  not  differ  from  augite  in  composition  ; 
but  since  the  difference  in  crystallization  is  connected  with 
a  difference  in  the  physical  conditions  attending  their  origin, 


DESCRIPTIONS   OF   ROCKS. 

and  since  rocks  of  each  kind  often  have  a  vast  extent  over 
the  earth's  surface,  the  distinction  as  to  whether  a  rock  is 
hornblendic  or  augitic  is  of  prominent  geological  interest. 

II.  CLASSES  OF  ROCKS. 

Kocks  are  of  different  classes,  according  to  their  texture 
and  origin. 

1.  FBAGMENTAL.     A  large  part  of  common  rocks  were 
formed  of  sand,  or  pebbles  and  sand,  and  are  only  consoli- 
dated sand-beds  or  gravel-beds  ;  and  other  related  kinds  are 
more  or  less  consolidated  mud-beds  or  clay-beds.     The  mud- 
beds  of  an  estuary,  or  of  the  shallow  seas  off  a  coast,  and  the 
stratified  sand  and  gravel  accumulations  of  sea-shores  and 
valley  formations,  are  precisely  the  kind  of  material  which 
by  consolidation  have  made  the  fragmental  rocks,  the  most 
abundant  rocks  of  the  earth's  surface.     Each  pebble,  grain 
of  sand,  and  constituent  particle  of  the  mud,  was  derived 
from  preexisting  rocks,  and  is  either  an  actual  fragment  from 
those  rocks,  or  else  a  fragment  altered  by  more  or  less  com- 
plete decomposition.     The  rocks  are  hence  called  fragmen- 
ted.    The  pebbles,  and  often  the  sands,  have  a  worn  surface, 
and  this  fact,  together  with  the  structure  of  the  beds,  affords 
evidence  that  they  are  fragmental.     They  are  also  the  sedi- 
mentary rocks  of  geology  ;  for  the  material  was  for  the 
most  part  carried  and  dropped  by  waters  as  sediment  is 
carried  and  dropped — the  waters  mainly  of  the  ocean  which 
then  covered  the  continents. 

2.  CKYSTALLINE.  Other  rocks  are  crystalline.    The  grains 
are  angular  instead  of  worn,  and  they  crowd  upon  or  pene- 
trate one  another  because  made  in  one  process  of  crystal- 
lization.    They  are  generally  angular  over  a  fractured  sur- 
face because  of  the  cleavage  planes,  like   the  grains  of  a 
surface  of  broken  iron.     Granite,  trap,  white  marble  are  ex- 
amples of  crystalline  rocks.     When  such  a  rock  is  distinctly 
granular  there  is  little  difficulty  in  deciding  upon  its  being 
a  crystalline  rock.     If  too  fine-grained  for  a  positive  conclu- 
sion with  the  aid  of  a  pocket-lens,  the  doubt  may  usually 
be  removed  by  tracing  it  along  to  places  where  it  is  coarser  ; 
and  if  none  such  offers,  by  the  preparation  of  thin  slices  for 
microscopic  examination. 

Crystalline  rocks  have  received  their  crystalline  texture 
in  different  ways. 


DESCRIPTIONS   OF   ROCKS.  413 

A.  By  cooling  from  fusion.  The  rocks  thus  made  are  called 
IGNEOUS  or  ERUPTIVE  rocks,  as,  for  example,  lavas  or  vol- 
canic ejections,  and  all  rocks  that,  like  trap,  have  come  up 
melted  through  fissures  in  the   earth's   rocky  crust.     The 
depth  of  the  liquid  source  of  such  eruptions  is  unknown. 
The  fact  that,  at  one  epoch,  material  of  the  same  kind  has 
sometimes  been  ejected  at  intervals  along  a  band  of  country 
a  thousand  miles  in  length,  from  northeast  to  southwest,  as 
on  the  Atlantic  coast  from  Nova  Scotia  to  South  Carolina, 
indicates  considerable  depth  in  such  cases.     They  may  be 
older  rocks  melted  over  and  thrust  up  to  the  surface  ;  but  if 
so,  the  remelted  rocks  were  in  many  cases  those  situated  deep 
in  the  earth's  crust,  far  below  all  the  strata  of  its  surface. 

B.  By  subjection  to  long -continued  heat  without  fusion, 
making  METAMORPHIC  rocks.  Through  this  means  fragmen- 
tal  or  sedimentary  strata,  over  areas  of  thousands  of  square 
miles,    and   many  thousands  of  feet  in  depth,  have  been 
simultaneously    crystallized,    turning  the   beds   that  were 
originally  made  from  sand,  gravel,  or  mud,  into  granite, 
gneiss,    and   other  related  rocks,    and  compact  limestones 
into  marble.     The  rocks  at  the  time  of  the  change  were 
generally  undergoing  extensive   mountain-making  uplifts, 
and  it  is  supposed  that  the  friction  attending  the  movements 
of  the  strata  may  have  been  an  important  source  of  heat  for 
the  change  or  crystallization  ;  and  that  the  diffusion  of  this 
heat  was  due  to  the  moisture  which  abounds  in  unaltered 
sedimentary  beds.     Metamorphic  strata  retain  their  former 
relative  order  of  superposition,  having  been  crystallized  in 
place,  that  is,  without  fusion.     Where  granite  has  been  the 
result,  it  is  probable  that  the  material  was  sometimes  re- 
duced to  a  pasty  state,  so  that  all  lines  of  the  original  bed- 
ding were  obliterated  ;  but  even  in  that  case,  the  granite  is 
generally  in  the  place  occupied  by  the  material  before  crys- 
tallization.    In  other  cases,  including  that  of  some  granites, 
there  was  not  even  this  degree  of  approach  toward  the  origi- 
nal condition  of  the  true  eruptive  rock.  During  the  upturn- 
ing, the  rocks  were  much  fractured,  and  the  fissures  so^made 
became  filled  with  the  materials  of  the  adjoining  or  subjacent 
rocks,  through  the  aid  of  the  heated  moisture  present,  mak- 
ing veins  ;  and  such  veins  differ  widely  from  those,  called 
'dikes,  that  were  made  when  the  fractures  descended  to  re- 
gions of  melted  rock,  so  that  the  fissures  became  filled  with 
ejected  material. 


414  DESCRIPTIONS   OP   ROCKS. 

Rocks  thus  metamorphosed  or  rendered  crystalline  are 
distinguished  as  metamorphic  rocks. 

C.  By  chemical  deposition.  Waters  often  hold  calcareous 
material  in  solution.  When  carbonic  acid  (carbon  dioxide) 
is  present  in  any  waters,  those  waters  will  take  up  calcium 
carbonate,  and  make  calcium  bicarbonate ;  and  when  the 
waters  evaporate,  the  calcium  carbonate  is  deposited.  This 
is  the  propess  by  which  stalactites  and  stalagmites  (p.  216) 
have  been  made,  and  so  also  calcareous  tufa  and  travertine 
(p.  432).  The  Gardiner  River  region  in  the  Yellowstone 
Park  is  noted  for  its  deposits  of  travertine. 

In  geyser  regions  there  are  siliceous  deposits  made  by  the 
hot  waters,  as  stated  on  page  240  ;  and  these  also  are  exem- 
plified in  the  Yellowstone  Park. 

Beds  of  tripolite  (p.  241)  sometimes  become  consolidated 
and  converted  into  chert  by  the  waters  that  penetrate  them 
— these  waters  containing  a  trace  of  alkali  or  enough  to 
enable  them  to  dissolve  some  of  the  tripoli  silica,  and  then 
a  deposition  taking  place  causing  consolidation.  The  flint 
and  chert  of  the  rocks  has  probably  had  generally  this  ori- 
gin. 

3.  CALCAREOUS  ROCKS  or  LIMESTONES.  Compact  lime- 
stones are  commonly  of  fragmental  origin.  They  have  been 
made  mainly  out  of  worn  or  ground-up  shells,  corals,  and  like 
calcareous  material  of  organic  origin — the  movements  of  the 
ocean  having  been,  and  still  being,  the  grinding  agency. 
They  were  consolidated  through  the  ocean's  waters  which 
penetrated  the  beds  taking  up  a  little  calcareous  material, 
and  then  depositing  it  again.  It  is,  in  one  sense,  metamor- 
phism.  But  when  such  compact  limestones  experience  true 
metamorphism,  at  the  same  time  with  other  strata,  they  be- 
come distinctly  crystalline-granular,  and  often  very  coarsely 
so,  making  crystalline  limestone  or  marble. 


III.  ON  SOME  CHARACTERISTICS  OF  ROCKS. 

1.  CRYSTALLINE  TEXTURE.  Crystalline  texture  varies  in 
coarseness  from  that  in  which  crystalline  grains  are  visible 
only  under  high  magnifying  power,  and  the  rock  is  as  apha- 
nitic  (p.  60)  as  flint,  to  that  in  which  they  are  very  coarse. 
Not  unfrequently  one  of  the  minerals  appears  in  large  crys- 
tals, distributed  through  the  mass — the  mass  being  made  of 


DESCRIPTIONS   OF    HOCKS. 


415 


the  rest  of  the  material  in  a  comparatively  fine-grained  con- 
dition. The  porphyry  of  the  ancients  was  a  rock  of  dark 
feldspathic  base,  sprinkled  all  through  with  light-colored 
feldspar  crystals  ;  and,  from  this  fact,  any  metamorphic  or 
igneous  rock  containing  such  disseminated  crystals  of  a 
feldspar  is  said  to  be  porphyritic. 

The  following  figures  illustrate  three  varieties  of  porphy- 
ritic rock.  The  first  represents  a  specimen  of  the  red  an- 
tique porphyry  of  Egypt — now  often  called  Rosso  antico — 
the  rock  which  gave  the  name  porphyry  to  geology,  a  kind 


Rosso  Antico.          Oriental  Verd-antique.        Porphyritic  gneiss. 

much  used  by  the  Romans  (though  not  by  the  Greeks  or 
Egyptians),  and  quarried  by  them  in  the  mountain  Djebel- 
Dokhan,  twenty-five  miles  from  the  lied  Sea,  in  latitude 
27°  20'.  Through  the  red  aphanitic  base  small  whitish 
crystals  of  orthoclase  are  thickly  distributed.  Figure  2  is 
from  a  polished  piece  of  green  antique  poryphyry.  The 
feldspar  crystals  are  comparatively  large,  and  the  compact 
base  has  a  dark  green  color.  Figure  3  represents  a  large 
crystal  of  orthoclase  with  the  gneiss  about  it,  from  porphy- 
ritic gneiss.  The  feldspar  crystals  in  porphyritic  gneiss  or 
granite  sometimes  measure  three  inches  by  one  and  a  half, 
and  again  only  a  fraction  of  an  inch.  These  orfchoclase 
crystals,  as  often  in  other  porphyritic  rocks,  are  twin  crys- 
tals, the  plane  of  cleavage  of  one  half  making  an  angle  of 
52°  23'  with  that  of  the  other  half.  Occasionally  large  crys- 


416 


DESCRIPTIONS    OF    ROCKS. 


tals  contain  small  crystals  of  mica  distributed  in  one  or 
more  layers  concentric  with  the  sides. 

The  clegree  of  coarseness  in  the  texture  of  a  crystalline 
rock  has  been  determined  chiefly  by  the  rate  of  cooling, 
in  connection  with  the  nature  of  the  material.  Relatively 
rapid  cooling  produces  a  fine  texture  or  grain,  and  very  slow 
cooling  a  coarser. 

A  melted  rock  may  cool  too  rapidly  to  become  stony 
throughout,  or  to  become  stone  at  all;  and,  in  the  latter 
case,  the  material  made  is  glass.  Common  melted  glass 
would  be  stone  on  cooling  if  the  process  were  gradual 
enough. 

Figures  4  to  6  represent  much-magnified  views  afforded 
by  transparent  slices  from  glassy  rocks,  in  three  of  their 
stages  between  the  pure  glassy  and  the  true  stony  state.  In 
4,  from  obsidian,  or  volcanic  glass,  of  Greenland,  there 
are  radiating  clusters  consisting  of  hair-like  microiites  (or 
microscopic  minerals),  called  tricliites  (from  the  Greek  tlirix, 
hair),  such  as  are  common  in  all  obsidians.  Fig.  5  shows 
the  texture  of  a  variety  of  pearlite,  a  light  gray  rock  of 

6. 


Tricliites  in  ob- 
sidian. 


Trichites  and  Fluidal 
texture  in  Pearlite. 


Microiites  in  a  Pitchstone 
from  Weisselberg. 


pearly  lustre  from  the  Montezuma  Range  in  the  Nevada 
Basin,  as  figured  by  Zirkel;  in  this,  trichite  clusters,  besides 
being  very  numerous,  are  arranged  in  lines  or  planes,  and 
some  of  the  tricliites  arc  powdered  with  pellucid  grains,  or 
globnlites,  which  are  incipient  crystals.  Zirkel  represents 
another  kind  in  which  the  radiating  trichites  are  each  a 
string  of  globulites.  Fig.  6  represents  a  pitchstone  from 


DESCRIPTIONS   OP  ROCKS.  417 

Weisselberg  (from  Rosenbusch),  in  which  the  microlites  are 
distinctly  crystalline  in  form,  and  some  give  evidence  that 
they  are  feldspar  crystals,  others  that  they  are  augite  and 
magnetite,  and  indicate  that  the  rock  is  intermediate  be- 
tween a  glass  and  a  doleryte.  Thus  there  is  a  passage  to 
ordinary  stone.  Trap  or  doleryte  has  been  used  for  making 
bottle-glass  ;  and  attempts  have  been  made  to  manufacture 
glass  directly  from  a  variety  of  granite  containing  little 
quartz. 

Eruptive  rocks,  that  have  come  up  through  fissures, 
often  have  glassy  particles  among  the  stony  in  the  part 
near  the  walls  of  the  fissure  when  not  so  through  the  inte- 
rior of  the  mass;  and  many  such  rocks,  covering  large  areas, 
have  glassy  grains  among  the  stony  grains,  or  a  glassy  mag- 
ma, because  the  cooling  generally  was  not  slow  enough  for 
complete  lapidification  ;  or  they  have  an  undefined  base, 
when  examined  in  thin  slices,  which  the  microscope  does 
not  resolve  into  crystalline  grains.  !Such  portions  of  a  rock 
are  described  as  unindivi dualized.  An  unindividualized 
base  exists  in  the  basalt  of  Truckee  Valley,  the  character  of 
a  slice  from  which,  highly  magnified,  is  given  in  fig.  7,  from 
Zirkel ;  feldspar  crystals,  of  their  usual  rectangular  forms 
(part  of  them  sanidin),  one  of  the  largish  crystals  of  chryso- 
lite, and  smaller  irregularly-shaped  augites,  are  imbedded  in 
a  base  which  consists  of  a  glass-like  substance  ;  and  in  this 
material  there  are  extremely  small  globulite  grains  which 
are  globules  of  devitrified  glass  or  incipient  crystals.  The 
glassy  unindividualized  base  occupies  the  spaces  among  the 
crystalline  portions. 

vrhese  differences  in  crystalline  texture  are  of  small  im- 
portance compared  with  differences  in  mineral  and  chemi- 
cal composition.  They  are  results  of  accidents,  and,  at 
the  best,  lead  only  to  a  distinction  of  varieties  among  kinds 
of  rocks.  The  presence  of  a  little  glass,  or  of  disseminated 
large  crystals  in  a  porphyritic  way,  does  not  make  the  rock 
essentially  different  in  kind.  If,  however,  the  glassy  na- 
ture is  manifest  in  the  external  appearance  of  the  mass,  ib 
is  convenient  to  call  the  rock  by  a  separate  name. 

Porphyritic  rocks  are  sometimes  named  as  if  porphyry 
was  a  distinct  kind  of  rock,  or  as  if  the  porphyritic  section 
of  a  kind  of  rock  merited  special  prominence.  But,  as  re- 
cognized beyond,  "felsyte-porphyry  "  is  porpliyritic  felsyte  ; 
f ( dioryte-porphyry"  is  porpliyritic  dioryte  ;  "  diabase-por- 


418 


DESCRIPTIONS    OF    ROCKS. 


phyry  "is  porpliyritic  diabase,  or,  since  diabase  cannot  be 
distinguished  mmeralogically  from  doleryte,  it  is  porpliy- 
ritic  doleryte  ;  and,  in  these  and  other  like  cases,  the  being 
porphyritic  is  a  characteristic  of  minor  value. 

Sometimes  igneous  rocks  exhibit  under  the  microscope  a 
fluidal  texture;  that  is,  the  material,  when  examined  in 
sections,  shows  wavy  lines  or  bands,  which  are  evidence  of 
a  former  fluid  state,  and  of  movement  or  flowing  when  in 
that  state.  One  variety  of  this  texture  is  represented  in  fig- 
ure 8  (from  Zirkel),  giving  a  magnified  view  of  an  eruptive 


7. 


8. 


ill 


Basalt  with  the  base  unindividu- 
alized. 


"  Rhyolyte  ;"  Fluidal  texture. 


rock  from  the  head  of  Louis  Valley,  Nevada  ;  and  another 
in  figure  5,  p.  416.  Such  rocks  have  been  comprised  under 
the  general  name  of  Rhyolyte  (from  the  Greek  for  flowing)  ; 
but  this  fluidal  texture  is'  presented  by  rocks  of  different 
mineral  constitution,  and  is  hence  not  a  proper  basis  for  a 
kind  of  rock. 

2.  ANHYDROUS  AND  HYDROUS  CRYSTALLINE  ROCKS.— 
Some  eruptive  rocks,  like  doleryte  or  trap,  occur  both  an- 
hydrous and  hydrous.  The  latter,  unlike  the  former,  have 
the  constituent  minerals  clouded  in  aspect,  however  thinly 
sliced,  and  often  changed  in  part  to  a  green  chlorite — a  hy- 
drous mineral — and  also  sometimes  to  other  hydrous  species. 
Such  rocks,  moreover,  have  less  lustre,  and  very  frequently 
they  are  amygdaloidal — that  is,  contain  little  cavities  that 
are  often  almond-shaped  (the  Latin  amygdalum  meaning 


DESCRIPTIONS   OF   ROCKS.  419 

almond),  which  were  made  by  steam,  or  vapor  of  some  kind, 
and  are  now  occupied  by  minerals.  This  hydrous  or  chloritic 
condition  is  due  to  alteration,  and  hence  such  rocks  are 
properly  only  varieties  of  the  anhydrous  instead  of  being 
distinct  kinds. 

The  change  was  probably  occasioned  by  subterranean  wa- 
ters, such  as  exist  as  streams  among  the  earth's  strata,  that 
were  encountered  by  the  liquid  rock  when  on  its  way  up  a 
fissure  toward  the  surface.  Hydrostatic  pressure  prevented 
the  waters  from  being  driven  back  by  the  heat,  and  conse- 
quently th*  vapors  were  forced  to  penetrate  the  igneous 
mass.  In  the  region  of  New  Haven,  Conn. — lying  at  the 
south  extremity  of  the  Connecticut  Valley — the  Triassic 
trap-dikes  of  the  western  border  of  the  region,  and  those 
outside  of  the  Trias,  east  or  west,  in  the  metamorphic 
rocks,  are  anhydrous,  while  those  in  the  middle  of  the  valley 
and  east  of  this  are  mostly  hydrous,  showing  a  difference  in 
exposure  to  the  waters  according  to  the  geographical  position 
of  the  dikes  in  the  valley.  Of  two  parallel  ranges  of  dikes, 
not  half  a  mile  apart,  and  following  concentric  curves  in 
their  courses  (situated  twenty  miles  and  more  north  of  New 
Haven),  one  (as  Percival  recognized)  is  amygdaloidal  and 
hydrous,  and  the  other  nearly  anhydrous;  and  the  positions 
of  the  two  kinds,  there  and  elsewhere  in  the  Connecticut 
Valley,  indicate  a  general  relation  between  the  direction  of 
the  present  valleys  and  that  of  the  subterranean  water-chan- 
nels of  Mesozoic  time. 

In  very  many  places  coal-like  "  inspissated  bitumen" 
occurs  in  the  amygdaloidal  cavities,  which  was  apparently 
derived  from  mineral  oil  that  the  action  of  the  heat  on  the 
Triassic  carbonaceous  shales  (in  some  places  abounding  in 
fossil  fishes)  had  caused  to  rise  in  vapors  and  penetrate  the 
melted  rock.  The  carbonic  acid  of  the  calcite  that  so  often 
constitutes  the  amygdules  probably  came  from  the  action 
of  the  heat  on  limestone  encountered  at  the  same  time. 
The  deoxidizing  action  of  the  carbohydrogen  vapors  is  sup- 
posed by  J.  Lawrence  Smith  to  account  for  the  metallic 
iron  found  in  some  trap  or  doleryte.  The  minerals  which 
constitute  the  amygdules  (see  p.  297)  are  largely  such  as 
may  have  been  made  by  the  aid  of  heat  and  moisture  out  of 
the  minerals  of  the  rock  itself  at  the  points  where  they  occur. 

The  water  that  caused  the  change  could  not  have  come  from  above 
after  the  rock  was  cooled ;  for  the  slight  surface  decomposition  the 


420  DESCRIPTIONS   OF   ROCKS. 

anhydrous  trap  now  undergoes  shows  that  such  waters  do  not  make 
their  way  down  :  and  moreover  the  results  could  not  have  been  pro- 
duced without  heat.  The  trap  has  not  been  subjected  to  a  metamor- 
phic  process  ;  for  the  Triassic  beds  are  unaltered  sandstone.  The  water 
was  not  from  the  deep-seated  source  of  the  erupted  trap,  for,  if  so,  the 
dikes  would  have  been  all  of  one  kind,  instead  of  being  part  hydrous 
and  part  anhydrous,  and  the  former  locally  distributed  just  as  subter- 
lanean  streams  of  water  are  likely  to  be. 

In  the  case  of  hydrous  metamorphic  rocks,  whether  con- 
taining chlorite,  talc,  or  a  hydrous  mica,  the  hydrous  min- 
erals were,  with  rare  exceptions,  made  at  the  time  of  the 
crystallization,  and  are  not  a  consequence  of  subsequent  al- 
teration. 

3.  DURABILITY  IK  ROCKS. — Durability  in  a  rock  is  due 
largely  (1)  to  compactness  and  fineness  of  texture;  and 
(2)  to  the  absence  of  any  ingredient  or  mineral  that  is  liable 
to  oxidation.  As  far  within  a  rock  as  water  and  air  can  gain 
access,  degradation  will  always  be  going  on,  and  most  rapidly 
in  all  crevices  along  their  walls.  Alternate  melting  and  freez- 
ing will  be  one  means  of  destruction ;  direct  chemical  action  of 
moist  air,  especially  the  carbonic  acid  it  contains  (p.  108), 
another  ;  the  wedging  apart  of  grains  caused  by  the  slightest 
deposits  and  oxidations,  through  infiltrated  waters,  another. 
In  granite  the  carbonic  acid  may  take  the  alkalies  out  of 
the  feldspar,  and  so  occasion  the  destruction  of  the  rock. 

Hence  the  practice  of  testing  the  durability  of  a  stone  for 
architectural  purposes,  by  putting  it  into  water,  and  then 
weighing  it,  after  some  days  of  exposure,  to  see  whether  it 
has  gained  in  weight,  is  a  good  one. 

Fineness  of  grain  gives  further  protection  against  destruc- 
tion. Alternate  heating  and  cooling  in  the  daily  passage  of 
the  sun  is  a  destroying  agency  of  great  effect,  especially  011 
coarse-grained  kinds.  Eocks  have  often  retained  the  glacier 
markings  upon  them  perfectly  fresh  until  now,  when  they 
have  had  a  covering  of  two  or  three  feet  of  earth ;  and  they 
have  lost  such  markings  after  a  few  years  of  exposure.  This 
happens  often  where  there  is  no  true  decomposition  or  ox- 
idation of  the  surface  portion  of  the  rock,  and  must  be  due 
largely  to  the  expansion  and  contraction  caused  by  changing 
temperature.  The  finer  the  grain  of  the  rock  the  less  the 
chance  for  this  action.  There  is  no  more  durable  rock  than 
a  roofing-slate  of  good  quality.  Granites,  when  well  pol- 
ished, will  usually  resist  long  all  weathering  agencies. 


DESCRIPTIONS   OF   ROCKS.  421 

The  presence  of  an  oxidizable  ingredient  is  a  common 
source  of  destruction.  Pyrite  occurs  in  grains  or  crystals 
in  almost  all  kinds  of  rocks  ;  and  it  generally  oxidizes 
easily  whenever  water  and  air  get  access  to  it.  Only  the 
firmest  crystals  resist  change,  and  these  not  always.  A  rock 
containing  even  a  little  pyrite  can  seldom  be  trusted  for 
architectural  purposes.  If  a  limestone  contain  a  few  per 
cent.,  or  even  one,  of  iron  or  manganese  replacing  part  of 
the  calcium,  it  has  a  source  of  destruction  within  it.  The 
iron  and  manganese  are  sure,  after  a  while,  to  oxidize  ;  the 
iron  will  give  rusty  stains,  and  the  manganese  turn  it  black, 
and  both  will  work  destruction.  A  chemical  trial  is  needed 
to  ascertain  the  fact  as  to  the  purity  or  not  of  the  rock. 
The  presence  of  iron  carbonate  (siderite  or  spathic  iron)  is 
the  occasion,  wherever  it  exists,  of  rapid  decomposition  as 
far  down  as  moisture  and  air  can  reach.  This  has  been  one 
source  of  the  changes  producing  the  great  beds  of  limonite 
(like  those  of  Western  Massachusetts,  Salisbury,  Connecti- 
cut, and  other  places),  in  which  the  rocks  are  sometimes  de- 
composed to  a  depth  exceeding  one  hundred  feet. 

It  is  a  fact  to  be  remembered  that  a  rock  which  has  stood 
the  weather  for  centuries  in  its  native  exposure  is  a  safe 
material  for  man's  structures  ;  and  one  that  is  crumbling  is 
worth  little  or  nothing. 

Durability  depends  much  on  the  climate.  In  Peru,  even 
sun-burnt  bricks  will  last  for  centuries. 

The  resistance  to  crushing  in  rocks  is  ascertained  by  sub- 
jecting cubes  of  a  given  size  to  pressure.  'In  recent  experi- 
ments by  P.  Michelot,*  Minister  of  Public  Works  in  France 
(whose  trials  numbered  over  10,000),  the  most  compact 
limestones,  weighing  2,700  kilograms  per  cubic  meter,  were 
crushed  by  a  weight  of  900  kilograms  per  square  centimetre. 
Compact  oolitic  limestone  of  Bourgogne  and  some  other 
French  localities,  weighing  2,600  to  2,700  kilograms,  bore 
700  to  900  kilograms  before  crushing.  Statuary  and  decora- 
tive marbles  bore  500  to  700  kilograms. 

Of  granitic  rocks  from  Brittany,  the  Cotentin,  the  Vosges, 
and  the  Central  Plateau  of  France,  weighing  2,600  to  2,800 
kilograms,  the  best,  which  admitted  of  polishing,  bore  1,000 
to  1,500  kilograms;  while  the  coarser  granites  of  Brest  and 


*  Exposition  Universelle  de  1873  a  Vieimc,  p.  401-432  ;  and  Annales  des  Pont*  et 
Chaussees,  1863,  1868,  1870. 


422  DESCRIPTIONS   OF   ROCKS. 

Cherbourg  and  the  syenyte  of  the  Vosges  bore  700  to  1,000 
kilograms ;  and  other  coarse  granites,  in  which  the  large 
crystals  of  feldspar  were  in  part  decomposed,  bore  only  400 
to  600  kilograms.  The  green  porphyry  of  Ternuay  (Haute 
Saone),  bore  1,360  kilograms;  the  "basalt  of  Estelle  (Puy 
de  Dome),  1,880  kilograms. 

In  trials  by  Gen.  Gilmore,  trap  of  New  Jersey  required 
to  crush  it  20.750  to  24,040  Ibs.  a  square  inch  (about  6  c. 
m.  sq.)  ;  granite  of  Westerly,  R.  I.,  17,750  ;  id.  of  Rich- 
mond, Va.,  21.250  ;  syenyte  of  Quincy,  17,750  ;  marble  of 
Tuckahoe,  N.  Y.,  12,950  ;  id.  of  Dorset,  Vt.,  7,612  ;  lime- 
stone of  Joliet,  111.,  11,250  ;  sandstone  of  Belleville,  N.  J-, 
10,250;  id.  of  Portland,  Ct.,  6,950;  id.  of  Berea,  0., 
8,300;  id.  of  Amherst,  0.,  6,650  ;  id,  of  Medina,  N.  Y., 
17,250  ;  id.  of  Dorchester,  N.  B.,  9,150. 

When  absorbent  rocks  are  thoroughly  wet  the  weight  re- 
quired to  crush  them  is  greatly  reduced.  To  crush  wet  chalk, 
according  to  trials  by  Delesse,  required  only  one-third  what 
it  did  when  stove-dried ;  and  for  the  limestone,  "  calcaire 
grossier,"  of  Vitry  and  other  localities,  mostly  one- third  to 
one-half.  Tournaire  and  Michelot  found,  for  the  chalk  of 
the  Paris  basin,  the  pressure  required  when  wet  two-ninths 
of  that  required  when  the  rock  had  been  dried  at  a  tempera- 
ture considerably  above  212°  F. 

Use  of  the  Microscope  in  the  Study  of  Rocks.  The  study  of 
thin,  transparent  slices  of  rocks  by  the  microscope  is  of  in- 
terest whether  the  crystalline  rock  be  coarse  or  fine  in  tex- 
ture ;  but  it  is  particularly  important  when  of  the  latter 
kind.  There  is  no  rock  so  opaque  that  it  cannot  be  made 
transparent,  or  at  least  translucent,  in  thin  slices.  Such 
slices  are  examined  by  means  of  a  polariscope-microscope. 
The  increased  use  of  the  microscope  in  the  investigation  of 
rocks  has  led  to  the  introduction,  by  way  of  distinction  in 
methods  of  study,  of  the  word  macroscopic.  An  investiga- 
tion may  be  carried  on  macroscopically ,  that  is,  without  the 
use  of  a  microscope,  excepting  a  pocket  lens  ;  or  microscopi- 
cally, that  is,  by  the  study  of  thin  slices  through  the  aid  of 
the  microscope  and  polariscope. 

The  more  important  points  ascertained  by  microscopic 
methods,  as  regards  the  mineral  constitution  of  a  rock,  are 
the  following : 

1.  The  presence  or  not  of  quartz;  of  a  feldspar;  of  a 
chloi'ite. 


DESCRIPTIONS   OF   ROCKS.  423 

2.  The  distinction  of  a  triclinic  feldspar  from  ortlioclase, 
the  former  showing  in  sections,  cut  in  any  direction  ex- 
cepting one,  commonly  several  parallel  spectrum  bands,  due 
to  multiple  twinning  in  the  crystal,  while  orthoclase  shows 
no  bands  of  the  kind,  or  at  the  most  but  two. 

3.  The  presence  or  not  of  hornblende  ;  this  mineral  hav- 
ing often  cleavage  lines  meeting  at  angles  of  124°,  and  being 
dichroic. 

4.  The  presence  or  not  of  pyroxene  ;   this  mineral  often 
showing  cleavage  lines  meeting  at  angles  of  87°  (nearly  a 
right  angle),  and  being  not  dichroic,  and  usually  distin- 
guished in  this  way  from  hornblende. 

5.  The  presence  or  not  of  mica,  its  cleavage  lines  and 
dichroism  affording  distinctive  characters. 

G.    The  presence  or  not  of  chrysolite  ;   of  magnetite,  its 
form  being  often  octahedral,  and  single  or  grouped  ;   of 

11. 


Magnetite  in  grouped         Liquid  Carbonic          Cube  of  Salt  in  a  solu- 
crystals.  Acid.  tion  of  the  same. 

points  or  portions  having  the  nature  of  glass,  and  therefore 
not  polarizing  light;  of  fluidal  lines;  of  liquid  carbonic  acid, 
and  of  various  other  inclusions.  Fig.  9  shows  a  common 
form  of  the  grouping  of  microscopic  magnetite  crystals 
in  an  eruptive  rock.  Fig.  10  represents  a  cavity  in  quartz 
nearly  filled  with  a  liquid,  b— the  small  bubble,  c,  showing 
the  part  not  occupied  by  it.  When  the  liquid  is  carbonic 
acid  the  air-bubble  disappears  on  raising  the  temperatw-e  to 
86°-95°  F.  Carbonic  acid  requires  a  pressure,  at  32°  F.,  of 
38-J-  atmospheres  to  retain  it  in  the  liquid  state  ;  and  hence 
occurs  liquid  only  in  quartz,  topaz,  and  a  few  other  miner- 
als. Fig.  11  (from  Zirkel)  shows  another  cavity,  containing, 
besides  a  liquid,  a  little  cube  and  microscopic  hornblende- 
like  acicular  crystals  ;  and  the  cube  is  supposed  to  be  com- 
mon salt  in  a  solution  of  salt.  Hexagonal  prisms  of  apa- 
tite (calcium  phosphate)  are  detected  by  the  microscope  in 


4.24:  DESCIUI'TIONS    OF    HOCKS. 

almost  all  kinds  of  igneous  and  metamorpliic  rocks,  includ- 
ing trap  or  doleryte. 

For  a  particular  account  of  the  distinguishing  character- 
istics of  minerals  studied  by  microscopic  methods,  reference 
must  be  made  to  treatises  on  the  subject. 

IV.  KINDS  OF  ROCKS. 

1.  Eocks  are  generally  mixtures   of  two,  three,  or  four 
prominent  mineral  constituents,  with  also  others,  it  may  be, 
of  less  importance.     Each  mineral  adds  a  distinctive  fea- 
ture, and  might  be  a  reason  for  a  new  name.     But  it  is 
usual  with  lithologists  to  base  the  distinction  into  kinds  of 
rocks  on  the  two  chief  minerals,  and  make  the  others  acces- 
sory species  and  the  basis  only  of  varieties.     This  method 
is  prompted  by  convenience,  and  also  by  the  fact  that  the 
more  important  characteristics  are  commonly  contained  in 
two  of  the  constituent  minerals.     It  has  many  exceptions, 
however,  and  particularly  where  a  third  mineral  has  special 
peculiarities  and  abundance. 

2.  Difference  in  kind  of  rock  is  naturally  based  on  dif- 
ference in  chemical  or  mineral  constitution,  and  identity, 
accordingly,   on  essential  identity  in  this   respect.     Conse- 
quently when  there  is  no  essential  difference  in  chemical  or 
mineral  constitution,  there  is  no  sufficient  reason  for  a  dis- 
tinction in  kind  or  a  difference  in  name,  unless  the  wide 
distribution  of  a  particular  variety,  and  the  permanence  in 
its  characters,  make  the  distinction  in  name  a  geological 
necessity. 

In  accordance  with  this  statement,  the  distinctions  among 
crystalline  rocks  of  coarse  or  fine  in  texture  ;  of  being  por- 
phyritic  or  not ;  of  containing  glassy  grains  among  the 
stony  or  not ;  of  being  foliated  or  not  in  crystallization,  are 
of  little  value  compared  with  the  real  mineral  constitution, 
anda^p  a  fit  basis  only,  at  the  best,  for  varieties.  But  the  two 
rocks  of  like  composition,  trachyte  and  felsyte,  retain  their 
characteristics  so  widely,  that  geology  needs  both  names, 
and  only  demands  that"  their  essential  identity  should  be 
held  in  mind. 

The  same  kind  of  rock  is  in  many  cases  both  of  metamor- 
phic  and  eruptive  origin  ;  still  the  difference  of  origin  is 
not  a  sufficient  basis  for  a  distinction  of  kind  unless  there 
is  some  marked  difference  between  them,  and  an  extended 


KINDS   OF   ROCKS.  425 

distribution  of  each,  that  makes  the  case  like  that  of  tra- 
chyte and  felsyte.  The  author  has  proposed  to  use  the  pre- 
fix meta  for  metamorphic  kinds  when  a  rock  occurs  both 
metamorphic  and  eruptive  ;  but  this  is  not  intended  to  indi- 
cate a  distinction  in  kind,  but  only  to  abbreviate  the  qualify- 
ing word  metamorphic. 

According  to  the  principles  above  stated,  a  rock  having 
oligoclase  or  albite  as  its  feldspar  constituent  cannot  rightly 
have  the  same  name  with  one  having  either  of  the  basic 
feldspars,  labradorite  or  anorthite,  as  an  essential  part, 
although  these  feldspars  are  all  embraced  under  the  decep- 
tive title  of  playioclase  (p.  275).  Between  anorthite  and 
oligoclase  there  is  a  difference  of  20  per  cent,  in  the  silica, 
and  the  former  is  simply  a  lime  feldspar  ;  and  the  contrast 
is  large  also  between  labradorite  and  oligoclase.  Again,  for 
a  like  reason,  as  already  explained  (p.  411),  a  mica-bearing 
rock  containing  little  or  no  hornblende  cannot  properly  be 
classed  with  hornblendic  rocks. 

3.  It  has  been  supposed  that  pre-Tertiary  crystalline  rocks 
differed  so  decisively  from  the   Tertiary  and  more  recent, 
that  those  of  the  two  series  should  not  bear  the  same  name. 
But  geology  knows  nothing  of  any  epoch  of  sudden  transi- 
tion in  the  mineral   nature  of  eruptive  rocks  at  the  com- 
mencement of  the  Tertiary  era ;  on  the  contrary,  it  shows 
that  the   kinds  made  before  and  after  this  epoch  are  alike 
in  mineral  constitution,  and  differ  not  always  even  in  tex- 
ture, but  only  in  the  greater  prevalence  after  the  Tertiary  of 
volcanic  or  subaerial   ejected  masses,  and  therefore  of  rocks 
of  the  texture  this   involves.     The  distinction  of  doleryte 
from  diabase,  with   others  similar,  is  of  this  chronological 
kind.     Rocks,  like  other  objects  in  science,  should  evidently 
be  named  from  what  they  are,   and  not  from  the  age  in 
which  they  may  have  been  made. 

4.  Since  quartz  is  the  most  abundant  of  all  the  minerals 
of  the  globe,  it  is  the  least  characteristic  of  the  ingredient^  of 
compound  rocks.     Eecent  lithologists  have  made  it,  in  sev- 
eral cases,  distinguish  only  a  section  under  a  kind  of  rock. 
Thus,   there   are   dioryte   and   quartz-dioryte,  felsyte  and 
quartz- felsyte,  trachyte  and  quartz-trachyte.     On  the  same 
principle  there  are  syenyte  and  quartz-syenyte,  as  adopted 
beyond. 

5.  The  division  of  crystalline  rocks  into  acidic  and  basic 
rocks  is  explained  on  p.  274     The  acidic  afford  on  analysis 


426  DESCRIPTIONS   OF   ROCKS. 

55  per  cent,  or  more  of  silica,  and  the  basic  usually  less 
than  52. 

6.  The  feldspars  are  divided,  according  to  their  bases, 
into  (1)  potash-feldspars,  including  orthoclase  and  micro- 
cline ;  and  (2)  those  which  may  be  designated  soda-lime- 
feldspars,  namely  the  species  albite,  oligoclase,  andesite, 
labradorite,  and  anorthite,  which  yield  either  soda,  or  lime, 
or  both,  on  analysis.  The  term  plagioclase  has  been  used 
for  the  latter  ;  but  it  is  no  longer  applicable  since  microcline 
is  plagioclase.  Under  the  heading  potash-feldspars,  as  used 
beyond,  leucite  also  is  included  ;  and  under  that  of  soda- 
lime-feldspars,  nephelite  and  sodalite,  and  also  the  minerals 
of  the  saussurite  group. 

The  kinds  of  rocks  are  described  under  the  heads  of — 

1.  FRAGMENTAL  BOCKS,  EXCLUSIVE  6F  LIMESTONES. 

2.  LIMESTONES,  OR  CALCAREOUS  EOCKS. 

3.  CRYSTALLINE  EOCKS,  EXCLUSIVE  OF  LIMESTONES. 

No  strongly  denned  limit  exists  between  the  fragmental 
and  crystalline  rocks.  But  still  they  are  for  the  most  part 
widely  diverse  in  character  and  aspect. 

In  the  names  of  rocks,  the  termination  ite  is  here  changed  to  yte,  as 
done  in  the  author's  "  System  of  Mineralogy  "  (1868),  in  order  to  dis- 
tinguish them  from  the  names  of  minerals.  Granite  is  excepted. 

I.   Fragmental  Rocks,  exclusive  of  Limestones. 

1,  Conglomerate. — A  rock  made  up  of  pebbles  or  of  coarse 
angular  fragments  of  rocks  of  any  kind,  (a)  If  the  pebbles 
are  rounded,  the  conglomerate  is  a  pudding-stone  ;  (b)  if 
angular,  a  breccia. 

Conglomerates  are  named  according  to  their  constituents,  siliceous 
or  quartzose,  granitic,  calcareous,  porpltyritic,  pumiceous,  etc. 

2r  Grit.— A  hard,  gritty  rock,  consisting  of  coarse  sand, 
or  sand  and  small  pebbles,  called  also  millstone  grit,  be- 
cause used  sometimes  for  millstones. 

3.  Sandstone. — A  rock  made  from  sand :  a  consolidated 
sand-bed. 

VARIETIES. — a.  Siliceous  or  Quartzose  ;  consisting  chiefly  of  quartz. 
b.  Granitic;  made  of  granitic  material  or  comminuted  granite,  c.  Mi- 
caceous ;  containing  much  mica.  d.  Argillaceous;  containing  much 
clay  with  the  sand.  e.  Gritty  ;  hard  and  containing  small  quartz  peb- 


KINDS   OF   ROCKS.  427 

bles.  f .  Ferruginous  ;  containing  iron  oxide  and  having  its  red  color, 
g.  Concretionary ;  made  up  of  concretions,  h.  Laminated ;  made  up 
of  thin  layers  or  laminae,  or  breaking  into  thin  slabs,  a  characteristic 
most  prominent  in  argillaceous  sandstones,  i  Friable  ;  crumbling  in 
the  fingers,  j.  Fossitiferous ;  containing  fossils. 

The  paving  stone  extensively  used  in  New  York  and  the  neighbor- 
ing States  is  a  laminated  sandstone,  of  the  upper  part  of  the  Hamilton 
group  in  geology,  quarried  just  south  of  Kingston,  and  at  many  other 
places  on  the  west  side  of  the  Hudson  River.  The  rock  is  remarkable 
for  its  very  even  lamination.  In  Western  New  York  and  in  Ohio,  the 
Devonian  sandstones,  above  the  Hamilton  group,  together  with  the 
Waverly  group,  afford  a  similar  flag-stone.  The  "  brown-stone"  used 
much  in  New  York  and  elsewhere  for  buildings,  is  a  dark-red  sand' 
stone  from  the  Triassic  formation,  and  is  quarried  at  Portland,  Conn., 
on  the  Connecticut  River,  opposite  Middletown.  A  lighter-colored 
"  brown-stone  "  or  "free-stone,"  of  the  same  age,  also  much  used  for 
buildings,  comes  from  Newark,  Belleville,  Little  Falls,  and  other  points 
in  Central  New  Jersey.  The  handsome  sandstone  of  light  olive-green 
tint,  much  employed  in  architecture,  is  from  the  Lower  Carboniferous 
group  in  New  Brunswick.  The  soft  white  sandstone,  in  much  esteem 
among  architects  because  so  easily  cut  and  carved,  comes  from  Ohio 
quarries,  in  beds  of  the  Carboniferous  ;  it  is  mostly  from  a  bed  about 
sixty  feet  thick,  called  the  "  Berea  grit/'  and  is  obtained  at  Bereaand 
Independence  in  Cuyahoga  County,  and  Amherst  in  Lorain  County,  and 
elsewhere. 

Pyrite  is  often  present  in  sandstones  used  for  building,  and  has  de- 
faced, and  is  destroying,  many  a  beautiful  structure  by  its  oxidation, 
and  the  consequent  decay  of  the  rock. 

Sandstones  absorb  moisture  most  easily  in  the  direction  of  the  bed- 
ding or  grain,  if  there  is  any  distinct  bedding  ;  and  hence  the  blocks, 
when  used  for  a  building  or  wall,  should  be  placed  with  the  bedding 
horizontal.  It  is,  further,  the  position  in  which  the  stone  will  stand 
the  greatest  pressure. 

Grindstones  are  made  from  an  even-grained,  rather  friable  sand- 
stone, and  are  of  different  degrees  of  fineness,  according  to  the  work 
to  be  done  by  them. 

Hard  siliceous  sandstones  and  conglomerates,  occurring  in  regions  of 
metainorphic  rocks,  are  called  "  granular  quartz,"  and  quartzyte  (p.435). 

4.  Sand-rock. — A  rock  made  of  sand,  especially  when  not 
of  siliceous  material.     A  calcareous  sand-rock  is  made  of  cal- 
careous sand  ;  it  may  be  pulverized  corals  or  shells,  such  as 
forms  and  constitutes  the  beaches  011  shores  off  which  living 
corals  and  shells  are  abundant. 

The  beach  sands  become  cemented  below  high- water  mark  into  a 
calcareous  sand-rock,  which  consists  of  layers  having  the  pitch  of  the 
surface  of  the  beach.  They  are  often  coarse,  calcareous  conglomerates. 

5.  Shale. — A  soft,  fragile,   argillaceous  rock,   having  an 
uneven  slaty  structure.     Shales  are  of  gray,  brown,  black, 
dull -greenish,  purplish,  reddish  and  other  shades. 


428  DESCRIPTIONS   OF   ROCKS-. 

VARIETIES. — a.  Bituminous  shale,  or  Carbonaceous  sliale  (Brand* 
schiefer  of  the  Germans),  impregnated  with  coaly  material  and  yielding 
mineral  oil  or  related  bituminous  matters  when  heated,  b.  Alum  shale; 
impregnated  with  alum  or  pyrites,  usually  a  crumbling  rock.  The 
alum  proceeds  from  the  alteration  of  pyrite  or  the  allied  pyrrhotite 
(p.  174). 

6.  Argillyte,    or   Phyllyte. — An   argillaceous   slaty  rock, 
like  shale,  but  differing  in  breaking  usually  into  thin  and 
even  slates  or  slabs.     Roofing  and  writing  slates  are  exam- 
ples.     It  is   sometimes  thick-laminated.      Unlike  shale,  it 
occurs  in  regions  of  metamorphic  rocks,  and  often  graduates 
into   hydromica,  chloritic,  and  mica  schists,  and  also,  on 
the  other  hand,  into  shale.      Often  called  Clay-slate. 

VARIETIES. — a.  Bluish-black,  b.  Tile-red,  c.  Purplish,  d.  Grayish. 
e.  Greenish;  f.  Ferruginous,  g.  Pyritiferous.  h.  Thick-laminated; 
affording  thick  slabs,  instead  of  slates,  i.  Thick-bedded;  a  massive 
rock,  affording  thick  blocks  or  masses,  j.  Staurolitic.  k.  Ottr clitic. 

Extensive  quarries  of  slate  exist  in  Vermont  at  Waterford.  Thet- 
ford,  and  Guilford,  in  the  eastern  slate  range  of  the  State  ;  in  North- 
field  in  the  central  range,  and  in  Castleton  and  elsewhere  in  the 
western  range,  the  last  of  Lower  Silurian  age  if  not  the  others.  There 
are  excellent  quarries  also  in  Maine  and  Pennsylvania.  The  rock  fur- 
nishes also  thick  slabs  for  various  economical  purposes.  A  trial  as 
to  water  absorption,  and  a  clos'e  examination  as  to  the  presence  of 
pyrite,  is  required  before  deciding  that  a  slate  rock  is  fit  for  use,  how- 
ever even  its  fissile  structure.  Kinds  with  a  glossy  surface  are  most 
likely  to  be  impervious  to  moisture. 

7.  Tufa. — A  sand-rock  or  conglomerate  made  from  com- 
minuted volcanic  or  other  igneous  rocks,  more  or  less  altered. 
Usually  of  a  yellowish-brown,  gray,  or  brown  color,  some- 
times red. 

VARIETIES. — a.  Dolcrytic  or  basaltic;  tufa  made  from  those  igneous 
rocks  that  contain  iron-bearing  minerals,  such  as  doleryte  (trap),  basalt, 
and  the  heavier  lavas  ;  it  is  usually  yellowish-brown  or  brown  in 
color,  sometimes  red  ;  and  often  consists  in  part  of  palagonite  (p.  312). 
b.  Trachytic;  made  of  the  f eldspathic  igneous  rock,  trachyte,  of  an  ash- 
gray  color,  or  of  other  light  shades,  c.  Pumiceous ;  made  of  frag- 
ments  of  pumice.  Pozzurtana-  is  a  light-colored  tufa,  found  in  Italy. 
near  Borne,  and  elsewhere,  and  used  for  making  hydraulic  cement, 
Wacke  is  an  earthy  brownish  rock,  resembling  an  earthy  trap  or  dole- 
ryte, usually  made  up  of  trappean  or  dolerytic  material,  compacted 
into  a  rock  that  is  rather  soft. 

8.  Sand.     Gravel. — Sand  is    comminuted   rock-material  ; 
but  common  sand  is  usually  comminuted  quartz,  or  quartz 
and  feldspar,  while  gravel  is  the  same  mixed  with  pebbles 
and  stones.     Sand  often  contains  grains  of  magnetite,   or 


KINDS    OF    ROCKS.  429 

of  garnet,  or  of  other  hard  minerals  existing  in  the  rocks  of 
the  region.  Occasionally  magnetite  or  garnet  is  the  chief 
constituent. 

Volcanic  sand,  or  Peperino,  is  sand  of  volcanic  origin, 
either  the  "cinders"  or  "ashes"  (comminuted  lava), 
formed  by  the  process  of  ejection,  or  lava  rocks  otherwise 
comminuted. 

9.  Green  Sand. — An  olive-green  sand-rock,  friable,  or  not 
compacted,  consisting  largely  of  glauconite.     See,  for  de- 
scription and  analysis,  p.  307. 

10.  Clay. — Soft,  impalpable,  more  or  less  plastic  material, 
chiefly  aluminous  in  composition,  white,  gray,  yellow,  red 
to  brown  in  color,  and  sometimes  black.     It  has  been  made 
chiefly  from  the  feldspars,  by  decomposition.    See  Kaolinite. 

VARIETIES.  —  a.  Kaolin,  purest  unctuous  clay.  b.  Potter's  day, 
plastic,  free  from  iron  ;  mostly  unctuous  ;  usually  containing  some 
free  silica.  Pipe-day  is  similar,  c.  Fire-brick  day,  the  same  ;  but  it 
may  contain  some  sand  without  injury,  d.  Ferruginous,  ordinary 
brick  day,  containing  iron  in  the  state  of  oxide  or  carbonate,  and  con- 
sequently burning  red,  as  in  making  red  brick,  e.  Containing  iron  in 
the  state  of  silicate,  and  then  failing  to  turn  red  on  being  burnt,  as  the 
clay  of  which  the  Milwaukee  brick  are  made.  f.  Alkaline  and  Vitri- 
fidble,  containing  2  '5  to  5  per  cent,  of  potash,  or  potash  and  soda, 
owing  to  the  presence  of  undecomposed  feldspar,  and  then  not  refrac- 
tory enough  for  pottery  or  fire-brick,  g.  Marly,  containing  some  car- 
bonate of  calcium,  h.  Weak  clay,  containing  too  much  sand  for  brick- 
making,  i.  Alum -bearing,  containing  aluminous  sulphates,  owing  to 
the  decomposition  of  iron  sulphides  present,  and  hence  used  for  mak- 
ing alum. 

The  red  pipestone  of  the  North  American  Indians  is  an  indurated 
clayey  rock^from  the  Coteau  de  Prairies  ;  it  has  been  named  Catlinite; 
and  the  gray  is  in  part  compact  argillyte. 

11.  Alluvium.    Silt.    Till. — Alluvium  is  the  earthy  deposit 
made  by  running  streams  or  lakes,  especially  during  times 
of  flood.    It  constitutes  the  flats  either  side,  and  is  usually  in 
thin  layers,  varying  in  fineness  or  coarseness,  being  the  re- 
sult of  successive  depositions. 

Silt  is  the  same  material  deposited  in  bays  and  harbors, 
where  it  forms  the  muddy  bottoms  and  shores. 

LCBSS  is  a  fine  earthy  deposit,  following  the  courses  of 
valleys  or  streams,  like"  alluvium,  but  without  division  into 
thin  layers.  Occurs  in  elevated  plains,  along  the  broad  parts 
of  large  valleys,  as  the  Mississippi,  Rhine,  Danube. 

Till  is  the  unstratified  sand,  gravel,  and  stones,  derived 
from  glaciers. 


430  DESCRIPTIONS   OF   ROCKS. 

Detritus  (from  the  Latin  for  worn)  is  a  general  term  ap- 
plied to  earth,  sand,  alluvium,  silt,  gravel,  because  the  ma- 
terial is  derived,  to  a  great  extent,  from  the  ivear  of  rocks 
through  decomposing  agencies,  mutual  attrition  in  running 
water,  and  other  methods. 

Soil  is  earthy  material  mixed  with  the  results  of  vegeta- 
ble and  animal  decomposition,  whence  it  gets  its  dark  color 
and  also  a  chief  part  of  its  fertility. 

12.  Tripolyte  (Infusorial  Earth).— Eesembles  clay  or  chalk, 
but  is  a  little  harsh  between  the  fingers,  and  scratches  glass 
when  rubbed  on  it.  Consists  chiefly  of  siliceous  shells 
of  Diatoms  with  often  the  spicules  of  sponges.  Forms 
thick  deposits,  and  is  often  found  in  old  swamps  beneath 
the  peat. 

This  soft  diatomaceous  material  is  sold  in  the  shops  under  the  name 
of  silex,  electro-silicon,  and  polishing  powder,  and  is  obtained  for  com- 
merce in  Maine,  Massachusetts,  Nevada,  and  California.  A  bed  ex- 
ceeding fifty  feet  in  thickness  occurs  near  Monterey  in  California  ;  and 
other  large  beds  in  Nevada  near  Virginia  City,  and  elsewhere.  It  is 
used  as  a  polishing  powder ;  in  the  manufacture  of  "soluble  glass;" 
and  also  mixed  with  nitro-glycerine  to  make  dynamite.  Occurs  some- 
times slaty,  as  at  Bilin,  Prussia  ;  and  also  hard  or  indurated,  from  con- 
solidation through  infiltrating  waters,  and  thus  graduates,  at  times, 
into  chert.  Consists  of  silica  in  the  opal  or  soluble  state. 

II.  Limestones  or  Calcareous  Rocks. 
1.  NOT  CRYSTALLINE. 

1.  Limestone.  Calcyte — Compact  uncrystalline  limestone 
usually  of  dull  gray,  bluish-gray,  brownish,  and  black  colors, 
sometimes  yellowish-white,  cream-colored,  nearly  white, 
and  red  of  different  shades  ;  in  texture,  varying  from  earthy 
to  compact  semi-crystalline.  It  consists  essentially  of  cal- 
cite  or  calcium  carbonate  (p.  215),  but  often  contains  clay  or 
sand,  or  other  impurities. 

VARIETIES. — The  varieties  depending  on  color  are  very  numerous, 
and  many  of  them,  when  pure  and  compact,  are  polished  and  used 
for  marble.  The  gray  and  black  colors  are  due  commonly  to  carbo- 
naceous material,  for  they  burn  white  ;  but  the  yellow,  red,  and  some 
other  kinds  to  the  presence  of  iron,  oxide.  There  are  also  :  a.  Fossil- 
iferous  or  shell  limestone,  b.  Coral  or  Madreporic  limestone,  c.  En- 
dinital  or  Crinoidal  limestone;  containing  crinoidal  remains  in  the 
form  mostly  of  small  disks,  d.  Ntfmmulitic  ;  containing  the  disk- 
shaped  fossils  called  Nummulites.  e.  Oolitic  limestone  ;  a  limestone 
having  an  oolitic  texture,  f.  Bird's  -  eye  limestone  ;  having  small 
whitish  crystalline  points  scattered  through  it,  a  rock  of  Western 


KINDS   OF   ROCKS.  431 

New  York,  of  the  Trenton  period  in  geology,  g.  Conglomerate  lime- 
stones. 

The  black  marble  of  the  United  States  comes  mostly  from  Shore- 
ham,  Vermont,  and  other  places  in  that  State,  near  Lake  Champlain, 
and  from  near  Plattsburg  and  Glenn's  Falls,  N.  Y. ;  also  from  Isle 
La  Motte.  A  pudding-stone  marble,  of  various  dull  shades  of  color, 
occurs  on  the  banks  of  the  Potomac,  in  Maryland,  50  or  00  miles  above 
Washington  ;  it  is  used  for  columns  in  the  interior  of  the  Capitol  at 
Washington. 

The  Portor  is  a  Genoese  marble  very  highly  esteemed  ;  it  is  deep 
black,  with  veinings  of  yellow  ;  the  most  beautiful  comes  from  Porto- 
Venese.  The  Nero-antico  marble  of  the  Italians  is  an  ancient  deep 
black  marble  ;  the  paragone  is  a  modern  one,  of  a  fine  black  color, 
from  Bergamo  ;  and  panno  di  morte  is  another  black  marble  with  a 
few  white  fossil  shells. 

A  beautiful  marble  from  Sienna,  brocatello  di  Siena,  has  a  yellow 
color,  with  large  irregular  spots  and  veins  of  bluish-red  or  purplish. 
The  mandelato  of  the  Italians  is  a  light  red  marble,  with  yellowish- 
white  spots.  The  Madreporic  marble  is  the  Pietra  stellaria  of  the 
Italians. 

Fire-marble,  or  lumachelle,  is  a  dark  brown  shell  marble,  having 
brilliant  fire-like  or  chatoyant  reflections  from  within. 

Ruin  marble  is  a  yellowish  marble,  with  brownish  shadings  or  lines 
arranged  so  as  to  represent  castles,  towers,  or  cities  in  ruins.  These 
markings  proceed  from  infiltrated  iron.  It  is  an  indurated  calcareous 
marl,  and  does  not  occur  in  large  slabs. 

Hydraulic  limestone  is  a  compact  kind  containing  some  clay,  and 
affording  a  quicklime  the  cement  from  which  will  set  under  water. 
An  analysis  of  a  kind  from  Rondout,  N.  Y.,  afforded  Carbonic  acid 
34-20,  lime  25  50,  magnesia  12 '35,  silica  15 '37,  alumina  9*13,  iron 
sesquioxide  2 '25.  In  making  ordinary  mortar,  quartz  sand  is  mixed 
with  pure  quicklime  and  water,  and  the  chemical  combination  is 
mainly  that  between  the  water  and  lime,  together  with  subsequently 
an  absorption  of  carbonic  acid.  With  "  hydraulic  cement,"  silica  and 
alumina  (that  of  the  clay)  are  disseminated  through  the  lime,  and 
hence  these  ingredients  enter  into  chemical  union  with  the  lime  and 
water,  and  make  a  much  firmer  cement,  and  one  which  "  sets  "  under 
water. 

Oil-bearing  limestones  occasionally  occur.  A  kind  used  for  build- 
ing in  Chicago,  of  the  Niagara  period,  becomes  spotted  or  streaked 
with  blackish  mineral  oil,  after  a  few  years'  exposure  to  the  weather. 

Some  of  the  pyramids  of  Egypt,  including  the  largest,  the  pyra- 
mid of  Cheops,  is  made  of  nummulitic  limestone  ;  and  this  is  tLe 
building  material  of  Aleppo,  the  range  of  mountains  between  Aleppo 
and  Antioch  being  composed  largely  of  this  cream -colored  rock. 

A  soft  Tertiary  limestone  occurring  in  the  vicinity  of  Paris  has 
afforded  a  vast  amount  of  rock,  of  an  agreeable  pale  yellowish  color, 
for  fine  buildings  in  Paris  ;  and  a  similar  rock  has  long  been  used  in 
Marseilles,  Montpellier,  Bordeaux,  Brussels,  and  other  places  in  West- 
ern Europe. 

Most  limestones  have  been  made  out  of  comminuted  shells,  corals, 
and  other  like  material  ;  and  when  of  dark  colors  or  black,  it  is  usu- 
ally owing  to  some  carbonaceous  matters  present  derived  from  the  de« 


4:33  DESCRIPTIONS   OP   ROCKS. 

composition  of  the  plants  or  animals  of  the  waters  in  which  they  were 
formed. 

When  burnt,  limestone  (CaO3C)  becomes  quicklime  (CaO),  through 
loss  of  carbonic  acid  (C0a)  ;  and,  at  the  same  time,  all  carbonaceous 
materials  are  burnt  out,  and  the  color,  when  it  is  owing  solely  to  these, 
becomes  white. 

2.  Magnesian  Limestone.  Dolomyte, — Carbonate  of  calcium 
and  magnesium,  but  not  distinguishable  in  color  or  texture 
from  ordinary  limestone.      The  amount  of  magnesium  car- 
bonate afforded  by  analyses  varies  from  a  few  per  cent,  to 
that  of  true  dolomite  (p.  55). 

Much  of  the  common  limestone  of  the  United  States  is  magnesian. 
That  of  St.  Croix,  Wisconsin,  the  "  Lower  Magnesian/'  afforded  Owen 
42 '43  per  cent,  of  magnesium  carbonate. 

In  some  limestones  the  fossils  are  magnesian,  while  the  rock  is 
common  limestone.  Thus,  an  Orthoceras,  in  the  Trenton  limestone  of 
Bytown,  Canada  (which  is  not  magnesian),  afforded  T.  S.  Hunt,  Cal- 
cium carbonate  56  00,  magnesium  carbonate  37 '80,  iron  carbonate  5  95 
=99-75.  The  pale-yellow  veins  in  the  Italian  black  marble,  called 
"Egyptian  marble,"  and  "portor"  (see  above),  are  dolomite,  accord- 
ing to  Hunt ;  and  a  limestone  at  Dudswell,  Canada,  is  similar. 

3.  Chalk. — A   white,  earthy  limestone,  easily  leaving  a 
trace  on  a  board.     Composition  the  same  as  that  of  ordi- 
nary limestone. 

4.  Marl. — A  clayey  or  earthy  deposit  containing  a  large 
proportion  of  calcium  carbonate — sometimes  40  to  50  per 
cent.     If  the   marl  consists  largely  of  shells  or  fragments 
of  shells,  it  is  called  /Shell-marl 

Marl  is  used  as  a  fertilizer  ;  and  other  beds  of  clay  or  sand  that  can 
be  so  used  are  often  in  a  popular  way  called  marl.  The  "Green 
sand  "  of  New  Jersey  (p.  429)  is  of  this  kind. 

5.  Travertine. — A  massive  limestone,  formed  by  deposi- 
tion from  calcareous  springs  or  streams.    The  rock  abounds 
on  the  river  Anio,  near  Tivoli,  and  St.  Peter's  at  Rome  is 
constructed  of  it.     The  name  is  a  corruption  of  Tiburtine. 
It  occurs  in  the  Yellowstone  Park,  along  Gardiner's  River. 

6.  Stalagmite.— See  page  216. 

2.  CRYSTALLINE  LIMESTONE. 

1.  Granular  or  Crystalline  Limestone  (Marble). — Limestone 
having  a  crystalline-granular  texture,  white  to  gray  color,  but 
often  of  reddish  and  other  tints  from  impurities.  It  is  a 
metamorphic  rock  ;  it  was  originally  common  limestone  ;  it 
became  crystalline  under  the  action  of  more  or  less  heat ;  in 


KINDS   OF   ROCKS.  433 

the  process  all  the  fossils  present  were  obliterated,  except 
in  some  cases  of  partial  metamorphism.  Its  impurities  are 
often  mica  or  talc,  trenwlite,  white  or  gray  pyroxene  or  scap- 
olite ;  sometimes  serpentine,  through  combination  with 
which  it  passes  into  ophiolyte  (p.  453)  ;  occasionally  clion- 
drodite,  apatite,  corundum. 

VAKIETIES. — a.  Statuary  marble;  pure  white  and  fine  grained, 
b.  Decorative  and  Architectural  marble;  coarse  or  fine,  white,  and 
mottled  of  various  colors,  and,  when  good,  free  not  only  from  iron  in 
the  form  of  pyrite,  but  also  from  iron  or  manganese  in  the  state  of 
carbonate  with  the  calcium,  and  also  from  all  accessory  minerals,  even 
those  not  liable  to  alteration,  and  especially  those  of  greater  hardness 
than  the  marble  which  would  interfere  with  the  polishing,  c.  Verd- 
antique,  or  Ophiolyte.  d.  Micaceous,  e.  Tremolitic;  contains  bladed 
crystallizations  of  the  white  variety  of  hornblende  called  tremolite. 
f.  Graphitic;  contains  graphite  in  iron-gray  scales  disseminated 
through  it.  g.  Chloritic;  contains  disseminated  scales  of  chlorite, 
h.  Ghondroditic;  contains  disseminated  chondrodite  in  large  or  smalt 
yellow  to  brown  grains. 

White  and  grayish-white  marble  is  abundant  in  Western  New  Eng- 
land, and  Southeastern  New  York  (Westchester  County).  The  tex- 
ture is  less  coarsely  crystalline  in  Vermont  than  in  Massachusetts,  the 
crystallization  of  the  limestone  as  well  as  of  the  associated  schists  in- 
creasing in  coarseness  from  the  north  to  the  south,  or  rather  south- 
southwest,  which  is  the  trend  of  the  limestone  belt.  Fine  marbles 
are  quarried  in  Dorset,  West  Rutland,  Pittsford,  and  other  places  in 
Vermont,  and  the  best  of  statuary  marble  occurs  abundantly  in  Pitts- 
ford.  The  whitest  marble  of  Rutland  is  not  as  firm  as  that  mottled 
with  gray,  owing  apparently  to  the  fact  that  it  was  made  white  by  the 
heat  that  crystallized  it  burning  out  any  carbonaceous  material ;  while 
at  Pittsford,  16  miles  to  the  north  of  Rutland,  it  is  very  firm,  and  is  white, 
probably,  because  it  was  made  with  less  heat  from  a  whiter  lime- 
stone. In  Vermont,  the  best  quarries  occur  where  the  strata  stand 
at  a  high  angle  :  the  layers  in  such  regions  were  subjected  to  great 
pressure  in  the  upturning  that  gave  them  this  position,  and  this  pres- 
sure has  soldered  many  layers  together  in  one  that  are  separate  where 
the  pressure  was  less  ;  consequently  blocks  as  large  as  an  ordinary 
house  might  be  obtained  at  some  of  the  quarries.  Good  marble  is  also 
quarried  in  Pennsylvania,  Maryland,  and  Tennessee.  One  of  the  most 
beautiful  marbles  from  deposits  of  crystalline  limestone  in  the  United 
States,  is  the  mottled  reddish-brown  from  East  Tennessee,  and  mainly 
from  Knox  and  Hawkins  counties.  Another  handsome  marble  is  the 
mottled  red  of  Burlington,  Vt.,  from  the  semi-crystalline  Winooski 
limestone  ;  and  a  still  finer  the  deeper  red  (or  cherry-red),  mottled  and 
veined  with  white,  of  Swan  ton,  Vt.,  from  the  same  limestone  on  the 
northern  borders  of  the  State. 

The  Carrara  marble  of  Italy,  the  Parian,  of  the  island  of  Paros  (the 
birthplace  of  Phidias  and  Praxiteles),  and  the  Pentelican,  from  quar- 
ries near  Athens,  Greece,  are  examples  of  crystalline  limestone.  The 
Carrara  marble  varies  in  quality  from  coarse  to  true  statuary  marble, 
and  the  best  comes  from  Monte  Crestola,  and  Monte  Sagro.  Out  of 


434  DESCRIPTIONS   OF   ROCKS. 

the  500  quarries  only  20  furnish  stone  for  the  sculptor.  The  amount 
of  marble  taken  out  from  the  quarries  in  1876,  was  120,000  tons, 
valued  at  $2,400,000  ;  and  of  this  40,000  tons  came  to  the  United 
States.  The  Cipoliti  marbles  of  Italy  are  white,  or  nearly  so,  with 
shadings  or  zones  of  green  talc. 

2.  Dolomyte. — Not  distinguishable  by  the  eye  from  gran- 
ular limestone. 

Part  of  the  marbles  above  referred  to  are  dolomyte.  This  is  the 
case  with  that  of  Westchester  County,  N  Y. ,  that  of  Canaan,  Con- 
necticut, and  of  Lee  and  Stockbridge,  Massachusetts. 

II.  Crystalline  Rocks,  exclusive  of  Limestones. 

The  crystalline  rocks  may  be  distributed  according  to 
their  composition  into  the  following  series  or  groups.  Each, 
excepting  the  first,  embraces  both  metamorphic  and  eruptive 
rocks. 

1.  Siliceous  rocks.    The  kinds  consisting  mainly  of  quartz 
or  opal  are  here  included.     The  first  of  those  mentioned, 
page  435,  is  intermediate  between  the  f ragmen tal  and  meta- 
morphic-crystalline  rocks.     The  opal  material  is  a  chemical 
deposit.     The  chert  of  sedimentary  formations  is  believed 
to  be  mainly  tripolite  consolidated  through  the  solution  of  a 
part  of  its  material  by  the  permeating  waters  and  its  sub- 
sequent desposition — tripolite  or  diatom  beds  being  made 
chiefly  of   opal-silica  which   is  readily  soluble   in  waters 
slightly  alkaline. 

2.  The  Mica  and  Potash-Feldspar  series.     These  are  emi- 
nently alkali-yielding  rocks,  both  the  mica,  whether  mus- 
covite,  biotite,  or  lepidomelane,  and  the  feldspar,  whether 
orthoclase  or  microcline,  affording  on  analysis,  as  explained 
on  page  411,  much  potash,  and  the  feldspars  often  also  some 
soda.     The  soda  feldspar,  albite  or  oligoclase,  is  a  common 
accessory  ingredient.     The  series  shades  off  into   a   rock 
that  is  chiefly  feldspar,  and  another  that  is  chiefly  mica ; 
and  in  these  two  extremes  the  amount  of  potash  yielded  is 
about  the  same.   Moreover,  as  leucite  is  essentially  a  potash- 
feldspar  in  ratio  and  composition  (see  page  411),  rocks,  con- 
sisting chiefly  of  leucite,  without  pyroxene  or  hornblende, 
belong  with  this  series.     Muscovite  and  biotite  commonly 
occur  together,  the  formation  of  biotite  having  been  deter- 
mined by  the  presence  of  some  iron  oxide  in  the  original 
material  from  which  it  was  made.     The  mica  is  sometimes 
a  hydrous  species  (page  313). 


KINDS    OF    ROCKS. 

3.  The  Mica  and  Soda-lime-Feldspar  series.     These  grani- 
toid rocks  are  equally  alkali-yielding  with  those  of  the  true 
granite  group,  but  the  alkali  is  mainly  soda.    The  nephelite 
(elseolite)  rocks  not  hornblendic  are  here  included,  although 
they  contain  in  general  some  microline  or  orthoclase. 

4.  The  Hornblende  and  Potash-Feldspar  series,  or  the  Sye- 
nyte  group.     In  this  series,  the  mica  of  the  granite  series  is 
replaced  by  the  non-alkaline  mineral,  hornblende.     Transi- 
tions between  the  granite  and  syenyte  rocks  are  common — a 
bed  that  is  true  mica  schist  often  becoming  hornblendic  ; 
the  same  specimen  may  have  mica  and  hornblende  crystals 
together,  or  parallel  mica  and  hornblende  layers,  and  then, 
not  far  beyond  the  schist  may  be  a  purely  hornblende  rock ; 
and  so  there  are  similar  transitions  in  other  parts  of  the 
two  series.     This  transition  in  a  stratum  of  mica  schist,  a 
metamorphic  rock,  indicates  merely  that  the  mud-bed  or 
sedimentary  stratum,  out  of  which   the   mica   schist  \^as 
made,  had  a  diminished  proportion  of  alkali  in  some  parts, 
and,  in  still  others,  a  complete  absence  of  alkali — which  is 
just  such  a  variation  as  might  be  looked  for  in  oceanic  sedi- 
ments, as  they  spread  over  a  wide  region.     The  hornblende 
may  be  replaced  by  epidote,  another  iron-bearing  mineral. 

5.  The  Hornblende   and  Soda-lime-Feldspar  series.      The 
soda-lime-feldspars,  in  this   series,  may  be   either   of  the 
triclinic  species,  from  albite  to  anorthite. 

6.  The  Pyroxene  and  Soda-lime-Feldspar  series.    The  soda- 
lime-feldspars  are  the  same  as  in  the  preceding.     Quartz 
is  very  rarely  present,   except  in  traces.     Potash  replaces 
soda  in  amphigenyte. 

7.  Pyroxene,  Garnet,  Epidote  and  Chrysolite  rocks,  con- 
taining little  or  no  Feldspar. 

8.  Hydrous  Magnesian  and  Aluminous  rocks, 
&.  Iron  Ore  rocks 

1.  SILICEOUS  ROCKS. 

1.  Quartzyte,  Granular  Quartz. — A  siliceous  sandstone, 
usually  very  firm,  occurring  in  regions  of  metamorphic 
rocks.  It  does  not  differ  essentially  from  the  harder  sili- 
ceous sandstones  of  other  regions.  Conglomerate  beds  are 
sometimes  included. 

VARIETIES. — a.  Massive,  b.  Schistose,  c.  Calcareous;  sometimes 
contains  disseminated  calcite  which,  where  the  rock  is  exposed  to 
weathering,  is  removed  and  leaves  the  rock  loose  in  texture,  or  cellu- 


436  DESCRIPTIONS  OF  ROCKS. 

lar.  d.  Micaceous,  e.  Hydromicaceous ;  it  graduating  at  times  into 
hydromica  or  mica  slate,  f.  Feldspathic,  sometimes  porpJiyritic  (the 
rock  Arkose),  or  like  granulite  in  its  disseminated  feldspar  ;  a  coarsely 
f  eldspathic  variety  occurs  north  of  Lenox,  Mass. ,  and  when  it  loses  its 
feldspar,  it  becomes  cellular,  like  buhrstone  ;  at  other  places,  as  in 
Cheshire,  Savoy,  and  eastern  Washington,  Mass.,  the  feldspar  of  a 
feebly-consolidated  quartzyte  has  been  leached  out  by  the  tiltrating 
waters,  and  the  rock  reduced  thereby  to  sand,  excellent  for  glass-mak- 
ing, while  in  some  localities  the  feldspar  so  removed  has  been  made 
into  valuable  beds  of  white  kaolin,  as  in  Brandon,  Vermont,  East  Shef- 
field, Mass.,  and  elsewhere,  g.  Gneissoid ;  containing  some  mica 
and  feldspar  in  layers,  and  so  graduating  toward  gneiss,  h.  Andalu- 
sitic  ;  containing  andalusite,  as  in  Mt.  Kearsarge  (Hitchcock),  i.  Tour- 
malinic  ;  containing  tourmaline.  The  vicinity  of  the  great  crystalline 
limestone  formation  of  the  Green  Mountain  region,  in  Western  New 
England  (in  Vermont  to  the  west  of  the  principal  ridge  of  the  Green 
Mountains),  includes  strata  of  quartzyts  of  great  thickness,  and  high 
summits  in  Bennington,  and  to  the  north,  and  also  south,  consist  of  it. 
In  several  places  the  quartzyte  strata  graduate  into,  and  also  alternate 
with,  hydromica  or  mica  slates,  and  in  Massachusetts  and  Connecticut, 
with  gneiss.  Between  Bernardston,  Mass.,  and  Vernon,  Vt.,  quartzyte 
occurs  in  large  beds,  and  also  graduates  into  gneiss  and  hornblendic 
rocks.  Quartzyte  exists  also  in  the  central  part  of  the  Southern  New 
Hampshire,  in  the  Archaean  area  of  Wisconsin,  and  in  the  Rocky 
Mountain  region,  j.  NovacuUtic-quartzyte,  or  Novaculyie  (Whetstone). 
Novaculyte  is  only  in  part  an  extremely  fine-grained  siliceous  rock.  Of 
this  nature  is  the  variety  from  Whetstone  or  Hot  Spring  Ridge,  in 
Arkansas.  This  ridge,  250  feet  in  height  above  the  Hot  Spring  Valley, 
is  made  up  of  the  beautiful  rock,  "equal,"  says  D.  D.  Owen,  "in 
whiteness,  closeness  of  texture,  and  subdued  waxy  lustre,  to  the  most 
compact  forms  and  whitest  varieties  of  Carrara  marble.  Yet  it  belongs 
to  the  age  of  the  millstone  grit."  Dr.  Owen  supposed  it  to  have  re- 
ceived its  impalpable  fineness  through  the  action  of  the  hot  waters  on 
sandstone.  An  analysis  of  the  rock  afforded  him  (Second  Rep.  Geol. 
Arkansas,  1860,  p.  24),  Silica  98'0,  alumina  0'8,  potash  0'6,  soda  05, 
moisture,  with  traces  of  lime,  magnesia  and  fluorine  O'l  =  100.  He 
states  that  alon^  the  southern  flank  of  the  ridge  there  are  over  forty 
hot  springs,  having  a  temperature  of  100°  F.  to  148°  F.  Solid  masses 
from  the  fine  rock  have  been  got  out  weighing  about  1,200  Ibs. ;  the 
coarser  varieties  are  made  into  stones  for  bench  tools. 

Beds  of  quartzyte  have  been  made,  like  those  of  sandstone,  out  of  the 
quartz  grains  of  older  rocks,  no  evidence,  chemical  or  geological,  favor- 
ing the  view  that  they  could  be,  or  have  been,  produced  by  chemical 
deposition.  Some  quartzytes  and  sandstones  have  had  part  of  the 
grains  converted  into  more  or  less  perfect  quartz  crystals,  from  the  de- 
position about  them  of  silica  in  the  process  of  consolidation — the  little 
heat  required  for  making  the  siliceous  waters  coming  from  the  earth's 
interior,  as  a  consequence  of  thick  accumulations  of  strata  above,  or 
from  the  friction  of  upturning,  or  from  warm  springs. 

2.  Itaeolumyte. — Schistose,  consisting  of  quartz  grains  with 
some  hydrous  mica  ;  on  account  of  the  mica  in  the  lamina- 
tion, it  is  sometimes  flexible,  and  is  called  flexible  sandstone. 


KINDS   OF  ROCKS* 


437 


Occurs  in  the  gold  regions  of  North  Carolina  and  Brazil,  and  diamonds 
are  supposed  to  be  sometimes  connected  as  to  origin  with  this  rock. 

3.  Siliceous  Slate.— Schistose,  flinty,  not  distinctly  granu- 
lar in  texture.     Sometimes  passes  into  mica  slate  or  schist. 

4.  Chert. — An    impure    flint    or   hornstone  occurring  in 
beds  or  nodules  in  some  stratified  rocks.     It  often  resem- 
bles fclsyte,  but  is  infusible.     Colors  various.     Sometimes 
oolitic.     Kinds  containing  iron  oxide  graduate  into  jasper 
and  clay  ironstone  ;  and  others,  occurring  as  layers  or  no- 
dules in  limestone   are  whitish,    owing  to   the   limestone 
material  they  contain.     Chert  sometimes  contains  cavities 
which  are  lined  with  chalcedony  or  agate,  or  with  quartz 
crystals. 

5.  Jasper  rock. — A  flinty  siliceous  rock,  of  dull  red,  yel- 
low, or  green  color,  or  some  other  dark  shade,  breaking  with 
a  smooth  surface  like  flint.     It  consists  of  quartz,  with  more 
or  less  clay  and  iron  oxide.   The  red  contains  the  oxide  in  an 
anhydrous  state,  the  yellow  in  a  hydrous ;  on  heating  the 
latter  it  turns  red. 

6.  Buhrstone. — A  cellular  siliceous  rock,  flinty  in  texture. 
Found   mostly  in   connection   with    Tertiary   rocks,    and 
formed  apparently  from  the  action  of  siliceous  solutions  on 
preexisting  fossil'iferous  beds,  the  solutions  removing  the 
fossils  and  leaving  cavities. 

Buhrstone  is  the  material  preferred  for  millstones.  The  buhrstone 
of  the  vicinity  of  Paris,  France,  has  long  been  largely  exported  for 
this  purpose.  Good  buhrstone  is  obtained  also  from  the  Tertiary  in 
Greenville  District,  South  Carolina,  100  miles  up  the  Savannah  River. 

7.  Fioryte.  (Siliceous  Sinter,  Pearl  Sinter,  Geyserite.) — 
Opal-silica,  in  compact,   porous,   or  concretionary  forms, 
often  pearly  in  lustre  ;  made  by  deposition  from  hot  sili- 
ceous  waters,    as   about   geysers   (Geyserite),   or   through 
the  decomposition  of  siliceous  minerals,  especially   about 
the  f  umaroles  of  volcanic  regions. 

Geyserite  is  abundant  in  Yellowstone  Park,  and  about  the  Iceland 
geysers  ;  after  long  exposure  it  crumbles  down  and  becomes  changed 
to  ordinary  silica,  or  quartz. 

2.  MICA  AND  POTASH-FELDSPAR  SERIES. 

1.  Granite. — Consists  of  quartz,  orthoclase,  and  mica,  and 
has  no  appearance  of  layers  in  the  arrangement  of  the  mica 
or  other  ingredients.  G.  =  2'5-2'8.  The  quartz  is  usually 
grayish-white  or  smoky,  glassy,  and  without  any  appearance 


438  DESCRIPTIONS  OF   ROCKS. 

of  cleavage.  The  feldspar  is  commonly  whitish  or  flesh- 
colored,  and  may  be  distinguished  from  the  quartz  by  its 
cleavage  surfaces,  which  reflect  light  brilliantly  when  the 
specimen  is  held  in  the  sunlight.  The  mica  is  usually  in 
small  bright  scales,  either  silvery,  brownish-black,  or  black 
in  color,  and  the  point  of  a  knife  carefully  used  will  easily 
split  them  into  thinner  scales  ;  the  silvery  mica  is  muscovite, 
but  sometimes  of  the  allied  hydrous  kinds,  margarodite  or 
damourite,  and  the  black  mica  is  usually  biotite,  though 
occasionally  the  allied,  more  iron-bearing,  species,  lepidome- 
lane.  Oligoclase  or  albite  is  very  often  present. 

Occurs  both  metamorphic  and  eruptive.  Metamorphic 
granite  may  often  be  seen  graduating  into  gneiss,  or  lying 
in  beds  alternating  with  gneiss. 

VARIETIES. — There  are,  A.  Muscovite  granites  ;  B.  Biotite  granites  ; 
C.  Muscovite-and-biotite  granites,  the  last  much  the  most  common. 
The  most  of  the  following  varieties  occur  under  each  except  the  horn- 
blendic,  which  is  usually  a  Biotite,  or  Muscovite-and-Biotite,  granite. 
There  is  also,  D.  Hydromica-granite.  a.  Common  or  Ordinary  granite  ; 
the  color  is  grayish  or  flesh-colored,  according  as  the  feldspar  is  white 
or  reddish,  and  dark  gray  when  much  black  mica  is  present.  Granite 
varies  in  texture  from  fine  and  even,  to  coarse ;  and  sometimes  the 
mica,  feldspar,  and  quartz — especially  the  two  former — are  in  large 
crystalline  masses.  An  average  granite  (mean  of  11  analyses  of  Lein- 
ster  granite,  by  Haughton)  affords  Silica  72*07,  alumina  14'81,  iron 
protoxide  and  sesquioxide  2'52,  lime  1*63,  magnesia  0'33,  potash  5'11, 
soda  2-79,  water  1-09=100-35.  b.  Porphyritic  granite;  has  the  ortho- 
clase  in  defined  crystals,  and  may  be  (a)  small  porphyritic,  or  (ft)  large 
porphyritic,  and  have  the  base  (y)  coarse  granular,  or  (6)  fine,  and 
even  subaphanitic.  c.  Albitic  granite;  contains  some  albite,  which  is 
usually  white,  d.  Oligoclase  granite  (Miarolite) ;  contains  much  oligo- 
clase.  e.  Microcline  granite ;  contains  the  potash  triclinic  feldspar, 
microcline.  f.  Hornblendic  granite;  contains  black  or  greenish-black 
hornblende,  along  with  the  other  constituents  of  granite,  g.  Black 
micaceous  granite ;  consists  largely  of  mica,  with  defined  crystals 
of  feldspar  (porphyritic),  and  but  little  quartz,  h.  lolitic ;  con- 
taining iolite.  i.  Globuliferous  granite;  contains  concretions  which 
consist  of  mica,  or  of  feldspar  and  mica.  j.  Oneissoid  granite;  a 
granite  in  which  there  are  traces  of  stratification;  graduates  into 
gneiss,  k.  Pegmatyte,  or  Graphic  granite ;  consists  mainly  of  ortho* 
clase  and  quartz,  with  but  little  mica  ;  but  the  quartz  is  distributed 
through  the  feldspar  in  forms  looking  like  oriental  characters. 

A  porphyritic  granite,  occurring  at  the  junction  of  the  andalusite 
mica-argillyte  (page  441)  of  the  White  Mountain  Notch,  N.  H.,  with 
the  Mt.  Willard  granite,  on  the  west  side  of  Mt.  Willard,  conformable 
with  the  bedding  of  the  argillyte,  has  the  argillyte  for  its  base  ;  and 
in  it  the  orthoclase  is  in  large  well-defined  crystals,  and  the  quartz 
in  double  six-sided  pyramids,  both  easily  separable  from  the  matrix  ; 
the  layer  is  six  to  twenty  feet  thick. 


KINDS   OF   ROCK.  439 

The  distinctions  as  to  kinds  of  rocks  between  metamorphic  and 
eruptive  granites  are  not  yet  made  out.  A  porphyritic  variety,  having 
the  base  fine-grained,  occurs  east  of  Parkview  Peak,  in  the  Rocky  Mts., 
which,  according  to  Hague,  is  eruptive  and  related  to  the  trachytes  of 
the  region.  The  granite  of  New  England  is  for  the  most  part  meta- 
morphic or  in  veins.  The  following  are  prominent  regions  of  the 
granite  quarries.  In  Maine :  at  Hallo  well,  a  whitish  granite,  some- 
times a  little  gneissoid  ;  at  Rockport,  whitish  ;  at  Clarke's  Island, 
spotted  gray  ;  at  Jonesbury,  flesh-red ;  also  in  the  Mt.  Desert  region! 
In  New  Hampshire,  at  various  places,  but  most  prominently  near  Con- 
cord, a  fine-grained  whitish  granite.  In  Massachusetts  at  several 
points,  especially  in  Gloucester  at  Rockport,  a  red  granite.  (The  Quincy 
"granite"  is  a  syenyte.)  In  Rhode  Island,  at  Westerly,  a  fine-grained 
whitish  granite.  In  Connecticut,  at  Millstone  Point  near  Niantic,  and 
at  Groton,  near  New  London,  a  fine-grained  whitish  granite  ;  at  Stoney 
Creek,  a  pale  reddish,  but  liable  to  large  micaceous  spots  ;  at  Ply- 
mouth, on  the  Naugatuck,  a  whitish  granite,  even  and  fine-grained, 
more  easily  worked  than  the  Westerly. 

2.  Granulyte.    (Leptinyte.) — Like  granite,  but  containing 
no  mica,  or  only  traces.     Metamorphic  and  eruptive. 

VABIETIES. — a.  Common  granulyte  ;  white  and  usually  fine  granu- 
lar, a  common  rock  in  Western  Connecticut  and  West  Chester  Co.,  New 
York.  b.  Flesh-colored;  usually  coarsely  crystalline,  granular,  and 
flesh-colored;  the  coarse  flesh- colored  "granite"  of  the  Eastern  or 
Front  Range  of  the  Rocky  Mts. ,  in  Colorado,  sometimes  called  Aplite, 
is  partly  of  this  kind  ;  it  contains  a  little  albite  or  oligoclase  with  the 
orthoclase.  c.  Garnetiferous.  d.  Hornblendic ;  containing  a  little 
hornblende — a  variety  that  graduates  into  syenyte.  e.  Magnctitic ; 
containing  disseminated  grains  of  magnetite,  a  kind  common  in 
Archaean  regions,  in  the  vicinity  of  the  iron  ore  beds,  occurring  in 
Orange  Co.,  N.  Y.,  and  south  in  New  Jersey,  and  also  at  Brewster's, 
Dutchess  Co.,  N.  Y.,  and  in  Kent  and  Cornwall,  Conn.  f.  Graphic 
(Pegmatyte)  ;  like  gr.  Ajhic  granite,  but  containing  no  mica.  The 
coarser  granulyte,  especially  that  of  veins,  is  often  called  pegmatyte 
when  not  graphic. 

3.  Gneiss. — Like   granite,  but  with  the  mica  and  other 
ingredients  more  or  less  distinctly  in  layers.     Gneiss  breaks 
most  readily  in  the  direction  of  the  mica  layers,  and  hence 
its  schistose  structure  ;  in  consequence  of  this  structure, 
many  kinds  may  be   got  out  in  slabs.     It  often  graduates 
imperceptibly  into  granite.     Metamorphic.  • 

VARIETIES.— Similar  to  those  under  granite,  a.  Porpliyritic.  b  Al- 
Utic  c  Oligodase-bearing.  d.  Hornblendic.  e.  Micaceous,  f.  Crloou- 
UProiis.  g.  Epidotic.  h.  Garnetiferous.  i.  Andalusitic;  contains  an- 
dalusite  in  disseminated  crystals,  j.  Cyanitic ;  contains  cyanite,  a 
variety  that  has  been  observed  on  New  York  Island,  and  also  in  New, 
town  Ct.  Bellows  Falls  and  elsewhere  in  N.  H.  k.  Graphitic;  con- 
tains graphite  disseminated  through  it.  1.  Quartzose ;  the  quartz 
largely  in  excess,  m.  Quartzytic  ;  consists  largely  of  quartz  in  grams, 
being  intermediate  between  quartzyte  and  gneiss,  a  variety  occurring 
just  northeast  of  Bernardstou,  Mass.  Fig.  3  on  page  415  represents, 


440  DESCRIPTIONS   OF   ROCKS. 

natural  size,  a  small  pioce  of  the  porphyritic  gneiss  of  Birmingham, 
Conn. 

Some  gneiss  is  very  little  schistose,  being  in  thick,  heavy  beds, 
granite-like,  while  other  kinds,  especially  those  containing  much 
mica,  are  thin-bedded,  and  very  schistose  ;  the  latter  graduate  into 
mica  schist.  The  so-called  granite  of  Monson,  Mass.,  is  a  granitoid 
gneiss.  Its  gneissoid  structure  facilitates  greatly  the  quarrying. 

4.  Protogine.  Protogiae-gneiss. — Coarse  to  fine  granular, 
granite-like  or  gneissoid  in  structure,  and  mostly  the  lat- 
ter ;  of  a  grayish-white  to  greenish-gray  color ;  consists  of 
quartz,  white  or  grayish- white,  rarely  flesh-red,  orthoclase, 
a  dark  green  mica  and  often  chlorite,  with  some  greenish- 
white  talc,  and  white  oligoclase.     Metamorphic. 

The  dark  green  mica  approaches  chlorite,  as  shown  by  Delesse,  in 
its  very  large  percentage  of  iron  oxide  (Fe20321'31,  FeO5  03),  but  it 
gave  him  only  0  90  of  water,  with  6 '05  of  potash.  Among  accessory 
minerals  are  hornblende,  titanite,  garnet,  serpentine,  magnetite.  In 
an  analysis  of  the  protogine  as  a  whole,  Delesse  obtained  Silica  74-25, 
alumina  11'58,  iron  oxide  2'41,  lime  1'OS,  water  0-97,  leaving  10*01  for 
potash,  soda  and  magnesia.  From  the  region  of  Mont  Blanc  and 
other  parts  of  the  Swiss  Alps. 

5.  Mica  Schist. — Consists  largely  of  mica,  with  usually 
much  quartz,  some  feldspar,  and,  on  account  of  the  mifti, 
divides  easily  into  slahs,  that  is,  is  very  schistose.     Usually 
both  of  the  potash  micas,  muscovite  and  biotite,  are  present, 
and  the  latter  (black  mica)  is  commonly  much  the  most 
abundant.    The  colors  vary  from  silvery  to  black,  according 
to  the  mica  present.     Often  crumbles  easily;  and  roadsides 
are  sometimes  spangled  with  the  mica  scales.    The  dissemi- 
nated scales  or  crystals  of  biotite  are  sometimes  set  trans- 
versely to  the  bedding.     Metamorphic. 

VARIETIES. — a.  Gneissoid ;  between  mica  schist  and  gneiss,  and 
containing  much  feldspar,  the  two  rocks  shading  into  one  another. 
b.  Hornblendic.  c.  Garnetiferous.  d.  Staurolitic.  e.  Cyanitic.  f.  An- 
dalusitic.  g.  Fibrolitic ;  containing  fibrolite.  h.  Tourmalinic.  i.  Cal- 
careous ;  limestone  occurring  in  it  in  occasional  beds  or  masses. 
j.  Graphitic,  or  Plumbaginous ;  the  graphite  being  either  in  scales  or 
impregnating  generally  the  schist,  k.  Quartzose;  consisting  largely  of 
quartz.  1.  Quartzytic  ;  a  quartzyte  with  more  or  less  mica,  rendering 
it  schistose,  m.  Specular,  or  ltdbyrite  ;  containing  much  hematite  or 
specular  iron  in  bright  metallic  lamellae  or  scales.  In  fine-grained 
mica  schist,  the  scales  of  mica  tire  sometimes  scarcely  visible  without 
a  lens. 

6.  Hydro-mica  Schist. — A  thin-schistose  rock,  consisting 
either  chiefly  of  hydrous  mica,  or  of  this  mica  with  more 
or  less   quartz.  ;  having  the  surface   nearly   smooth,    and 


KINDS   OF   ROCKS.  441 

feeling  greasy  to  the  fingers  ;  pearly  to  faintly  glistening  in 
lustre ;  whitish,  grayish,  pale  greenish  in  color,  and  also  of 
darker  shades.  For  analyses  of  hydrous  micas  see  page  313. 
Metamorphic. 

This  rock  used  to  be  called  talcose  slate,  but,  as  first  shown  by  Dr.  C. 
Dewey,  it  contains  no  talc.  It  includes  Parophite  schist,  Damourite 
slate  and  Sericite  slate  (Glanz-Schiefer  and  Sericit-Schiefer  of  the  Ger- 
mans.) 

VARIETIES.— a.  Ordinary  ;  more  or  less  silvery  in  lustre,  b.  Chlo- 
ritic  ;  contains  chlorite,  or  is  mixed  with  chlorite  slate,  and  has  there- 
fore spots  of  olive-green  color;  graduates  into  chlorite  slate,  c.  Gar- 
netiferous.  d.  Pyritifcrous ;  contains  pyrite  in  disseminated  grains  or 
crystals,  e.  Mugnetitie  ;  contains  disseminated  magnetite,  f .  Quart- 
zytic;  consists  largely  of  quartzyte,  or  is  a  quartzyte  rendered  schistose 
and  partly  pearly  by  the  presence  of  hydrous  mica,  as  is  well  seen  in  a 
ridge  northeast  of  Rutland,  Vermont,  which  consists  partly  of  quartzyte 
and  partly  of  hydromica  schist. 

7.  Paragonite    Schist. — Consists   largely   of  the   hydrous 
soda  mica  called  paragonite  (p.  314);  but  in  other  characters 
resembles  hydromica  schist.     Metamorphic. 

8.  Minette. — Brown  to  black,  fine-grained,  compact,  not 
distinctly   schistose  ;    consisting   of    biotite    (according   to 
the  description  and  analysis  of  Delesse)  and  orthoclase ; 
contains  also  a  little  hornblende.     Occurs  in  beds  in  the 
Vosges,  France,  associated  with  granite,  syenytc,  and  other 
crystalline  rocks.     Sometimes  feebly  porphyritic  and  small- 
concretionary,  the  concretions  consisting  mainly  of  ortho- 
clase.  Made  eruptive  by  Delesse,  and  metamorphic  by  some 
later  authors.     Approaches  argillyte  in  aspect. 

9.  Greisen. — Massive,  without  schistose  structure.  A  mix- 
ture of  granular  quartz  and  mica,  in  scales.    The  mica  may 
be  muscovite,  lepidolite,  or  biotite.    It  is  a  granite  with  the 
feldspar  left  out,  and  occurs  in  regions  of  gneiss,  granite, 
or  quartz vte,  and  sometimes  graduates   into  these  rocks. 
Metamorphic. 

Occurs  in  characteristic  form  at  Zinnwald,  in  the  Erzgebirge,  where 
it  sometimes  contains  tin  ore  as  an  accessory  ingredient,  and  is  fre- 
quently penetrated  by  veins  of  tin ;  also  in  the  tin  ore  regions  of 
Schlackenwald  and  Cornwall.  Occurs  in  the  region  of  quartzyte,  horn- 
blendic  rocks  and  gneiss,  of  Upper  Silurian  age,  between  Bernards- 
ton,  Mass  ,  and  Vernon,  Vt.,  within  three  miles  northeast  of  the  former 
place,  and  also  near  Vernon  ;  but  at  this  place  it  contains  usually  a 
little  hornblende,  making  it  a  very  tough  rock,  and  is  intermediate 
between  the  quartzyte,  homblendic  rock  and  mica  schist  of  the  region. 

10.  Mica- Argillyte  or  Mica-Phyllyte. — Includes  the  part  of 
argillyte  (p.  428)  which  has  the  composition  nearly  of  a  hy- 
drous mica,  like  that  of  the  White  Mountain  Notch,  where 


442  DESCRIPTIONS   OF   ROCKS. 

much  of  it  is  andalusitic.  Analysis  of  this  White  Mountain 
rock,  by  Hawes,  afforded  Silica  46*01,  alumina  30'56,  iron 
sesquioxide  1*44,  iron  protoxide  6*85,  manganese  protoxide 
0*10,  magnesia  1*42,  soda  1*12,  potash  6 '66,  titanium  dioxide 
1*91,  water  4*13  =  100-22.  (Compare  with  analyses  of  hy- 
drous muscovite,  or  margarodite.)  Metamorphic. 

11.  Felsyte.  Quartz-Felsyte.   (Euryte,  Petrosilex.) — Com- 
pact orthoclase,  with  often  some  quartz  intimately  mixed; 
fine  granular  to  flint-like  in  fracture;   sometimes  contains 
oligoclase.     Colors   white,  grayish-white,  red,  brownish-red 
to  black.     G.^2'6-2'7.     Both  metamorphic  and  eruptive. 

VAEIETIES. — There  are  two  sections,  I.  Felsyte,  and  II.  Quartz- 
Felsyte,  and  under  each  occur  the  following  varieties,  a.  Porphyritic 
FeUyte,  or  Porphyry  ;  containing  the  feldspar  in  small  crystals  distri- 
buted through  the  compact  base  ;  color  red  and  of  other  shades  ;  called 
sometimes  Quartz-porphyry,  when  the  base  is  a  quartz-felsyte.  b.  Con- 
glomerate fclsyte  ;  containing  pebbles,  as  at  Marblehead,  Mass.,  and  in 
the  White  Mountains,  c.  OUyoclase-bearing  ;  containing  this  triclinic 
feldspar  intimately  blended  with  the  orthoclase.  d.  Cellular  or  amyg- 
daloidal.  e.  Elvanyte  ;  essentially  a  quartzose  felsyte,  of  gray,  bluish- 
gray  to  brown  and  red  colors,  and  often  containing  disseminated  grains 
or  crystals  of  quarfcz  and  feldspar,  and  some  oligoclase  ;  some  compact 
slate-rock  has  the  sams  composition.  Occurs  in  Cornwall. 

The  metamorphic  and  eruptive  kinds  are  not  easily  distinguished. 
The  former  occurs  associated  with  sedimentary  strata,  and  often  con- 
tains pebbles  or  other  evidence  of  fragmental  origin  ;  while  the  lat- 
ter is  frequently  in  dikes,  that  is,  fills  the  fissures  through  which  it 
was  ejected.  Some  of  the  eruptive  felsyte  has  nearly  the  aspect  of 
trachyte,  with  which  rock  it  is  identical  in  composition.  Much  of  the 
red  porphyry  contains  hornblende  with  the  feldspar  of  the  base,  and 
has  the  constitution  of  dioryte  (p.  447). 

12.  Porcelanyte.    (Porcelain  Jasper.)— A  baked  clay,  hav- 
ing the  fracture  of  flint,  and  a  gray  to  red  color;  it  is  some- 
what fusible  before  the  blowpipe,   and  thus  differs  from 
jasper.   Formed  by  the  baking  of  clay-beds,  when  they  con- 
sist largely  of  feldspar.   Such  clay-beds  are  sometimes  baked 
to  a  distance  of  thirty  or  forty  rods  from  a  trap  dike,  and 
over  large  surfaces  by  burning  coal  beds.     Metamorphic. 

13.  Trachyte.  Quartz-Trachyte. — Consists  mainly  of  feld- 
spar, which  is  partly  in   glassy  crystals,   either  sanidin  or 
oligoclase  ;  and,  owing  to   the   angular  forms  of  the  glassy 
feldspar  and  the  porosity  of  the  rock,  the  surface  of  frac- 
ture is  rough,  whence  the  name  from  the  Greek  trachus, 
rough.      Sometimes  contains  disseminated  quartz,  and  is 
then  quartz-trachyte.    Color  ash-gray,  greenish-gray,  brown- 
ish-gray, but  sometimes  yellowish  and  reddish.     G.  =2'5- 
2*7.     Besides  the  feldspar  there  are  distributed,  somewhat 


KINDS    OF   ROCKS.  443 

sparingly,  through  the  mass,  in  many  kinds,  minute  needles 
of  hornblende,  crystals  or  scales  of  biotite,  magnetite  ;  some- 
times nephelite,  haiiynite,  tridymite.  Apatite  exists  in  the 
rock  in  microscopic  forms,  and  there  is  also  more  or  less  of 
the  rock  in  a  glassy  state.  Sometimes  contains  augite,  and 
has  a  higher  specific  gravity.  Quartz-trachyte  has  often 
nearly  the  composition  of  granite  in  which  there  is  little 
mica.  Eruptive  only. 

VARIETIES. — The  two  principal  divisions  under  each,  trachyte  and 
quartz-trachyte,  are  :  A.  Kanidin-trachyte,  in  which  the  mass  is  chiefly 
sanidin ;  and  B.  Oliyodasc-trachyte,  or  Domyte,  in  which  it  is  partly 
oligoclase  ;  but  the  two  graduate  into  one  another.  Both  occur  por- 
pliyritic  with  tabular  crystals  of  feldspar ;  and  in  the  latter  (as  at 
the  Drachenfels)  the  tables  are  sanidin.  They  graduate  into  vesicular 
or  scoriaceous  trachyte. 

Trachyte,  according  to  Reyer  and  Suess,  occurs  in  the  region  of  the 
Euganean  Hills  of  Tertiary,  Cretaceous  and  Jurassic  age  ;  and  the 
f  elsyte  of  Paleozoic  age  is  often  hardly  distinguishable  from  it,  while 
identical  with  it  in  composition. 

Trachyte  and  quartz-trachyte,  graduate  also  into  felsyte-like  volcanic 
rocks  of  like  constitution,  porphyritic  or  not  so.  The  latter  sometimes 
shades  into  rocks  of  semi-glassy  nature  called 

14.  Pearlstone,  when  somewhat  pearly  in  lustre;  PITCHSTOXE 
when  having  a  pitch-like  lustre;  and  these  into  the  glassy 
volcanic  material  called  Obsidian.    These  glassy  rocks  often 
contain  spherules  which  are  concretions  consisting  of  feld- 
spar with  some  quartz.     Pumice  is  a  light,  porous,  feldspa- 
thic  scoria,  with  the  pores  capillary  and  parallel.     Ordina- 
ry obsidian,  that  consists  chiefly  of  feldspar,  and  is  hence 
nearly  free  from  iron,  belongs  here;  the  rest  of  it  belonging 
with  the  augitic  igneous  rocks. 

15.  Leucityte. — A  grayish  rock  consisting  chiefly  of  leucite 
in  a  felsitic  state,  with  disseminated  leucite  crystals.   Occurs 
at  Point  of  Rocks,  Wyoming  Territory,  according  to  King 
and  Zirkel.     It  differs"  from  amphigenyte,  in  containing  no 
pyroxene,  or  only  traces  of  it. 

3.   MICA  AND  SODA-LIME-FELDSPAR  ROCKS. 

I.    NOT  CONTAINING  NEPHELITE. 

1.  Hemi-dioryte.  (Mica-dioryte,  Soda-granite.)— A  gran- 
ite-like rock,  in  which  the  feldspar  is  chiefly  oligoclase  ;  it 
contains  much  biotite,  with  usually  some  quartz,  and  often 
some  hornblende.  Occurs  at  Stony  Point,  on  the  Hudson, 


444  DESCRIPTIONS   OF   ROCKS. 

and  near  Cruger's,  in  the  town  of  Cortland,  N.  Y.,  at  the 
latter  place  often  graduating  into  a  granite-like  dioryte. 

Kersantyte  is  described  by  Delesse  as  consisting  of  biotite  and  oligo- 
clase,  with  some  quartz,  frequently  hornblende  in  needles,  and  mag- 
netite ;  from  the  Vosges,  the  Saxon  Erzgebirge,  and  Nassau.  Kersan- 
ion  is  a  similar  rock,  containing  no  hornblende,  from  near  Brest,  and 
from  Quimper,  in  Brittany.  Both  of  these  rocks  have  been  called  mica- 
dioryte. 

Kinzigyte^  is  a  compact  and  schistose  granular-crystalline  rock,  con- 
sisting of  biotite,  oligoclase,  and  garnet,  without  quartz,  and  contain- 
ing, as  accessory,  microcline,  iolite  and  fibrolite  ;  from  Kinzig,  north 
part  of  Black  Forest. 

II.    CONTAINING    NEPHELITE. 

1.  Miascyte. — Granitoid   to  schistose,   and  consisting  of 
microcline,  massive  nephelite    (elaeolite),   sodalite,  biotite, 
along  with  some  quartz,  and  often  some  zircon,  pyrochlore, 
monazite  and  other  minerals.     A  related  nephelite  rock  oc- 
curs on  Pic  Island,   Lake    Superior.     Named  by  G.  Rose, 
from  Miask  in  the  Ilmen  Mountains,  where  it  has  a  wide 
distribution.     Metamorphic. 

2.  Ditroyte. — A  coarse  to  fine-grained  rock,  consisting  of 
microcline, nephelite  (elasolite),  and  sodalite.  From  Ditro  in 
Eastern  Transylvania,  where  it  is  associated  with  syenyte 
and  mica  schist  and  lies  between  these  two  rocks. 

3.  Phonolyte.    (Clinkstone.) — Compact;  of  grayish,  blue, 
and  other  shades  of  color  ;  more  or  less  schistose  or  slaty  in 
structure;  tough,  and  usually  clinking  under  the  hammer, 
like  metal,  when   struck,  whence  the  name.     G.=2vk-2'7. 
Consists  of  glassy  feldspar  (orthoclase  or  oligoclase),  with 
nephelite  and  some  hornblende.     G.  Jenzsch  gives,  for  the 
composition  of  the  Bohemian  phonolyte,  Sanidin  (glassy  or- 
thoclase) 53-55,  nephelite  3T76,  hornblende  9-34,  sphene  3-67, 
pyrite  0-04=98*36.     Under  treatment  with  acids  the  nephe- 
lite is  dissolved  out.    Nosean  and  hauynite  occur  in  some 
phonolyte.     Eruptive  only. 

4.   HORNBLENDE  AND  POTASH-FELDSPAR  SERIES. 

In  this  series  the  hornblende  is  sometimes  replaced  by 
epidote,  another  anhydrous  iron-bearing  mineral,  yielding 
on  analysis  little  or  110  alkali  ;  microcline  is  often  present 
as  well  as  orthoclase.  The  species  graduate  into  kinds  con- 
sisting almost  solely  of  hornblende.  Biotite  is  often  pres- 
ent as  an  accessory  mineral. 


KINDS   OF   ROCKS.  445 

I.    NOT   CONTAINING   NEPHELITE. 

1.  Syenyte.  Quartz-Syenyte, — A  granitoid  rock  consisting  of 
hornblende  and  orthoclase,  with  or  without  quartz.  Oligo- 
clase  and  biotite  are  often  present.  The  quartziferous  va- 
riety, or  qudrtz-syenyte,  includes  the  syenyte  of  the  obe- 
lisks and  pyramids  of  Egypt.  Like  that,  the  rock  is  often 
flesh-colored  ;  but  whitish  and  grayish  varieties  are  also 
common.  The  Saxon  syenyte,  without  quartz,  afforded 
Silica  59*83,  alumina  16*85,  iron  protoxide  7*01,  lime  4*43, 
magnesia  2'61,  potash  6*57,  soda  2*44,  water  1*29,  and  Gr.  = 
2- 75-2 -90.  Metamorphic  and  eruptive.  Similar  varieties 
occur  under  both  divisions  of  syenyte. 

VAEIETIES. — a.  Porphyritic.  b.  AlUtic  ;  containing  albite  in  addi- 
tion to  the  constituents  of  true  syenyte.  c.  Oligodase-bcaring.  d.  Mi- 
caceous ;  containing  disseminated  black  mica,  which  is  usually  bio- 
tite, and  sometimes  lepidomelane.  e.  Garnetiferous.  f.  Epidotic  / 
containing  disseminated  epidote.  The  gray  "  granite  "  of  Quincy, 
Massachusetts,  south  of  Boston,  extensively  quarried  for  architectural 
piirposes,  is  a  quartz-syenyte,  consisting  of  orthoclase,  black  to  dark 
green  hornblende,  and  quartz,  with  some  triclinic  feldspar.  Quartz- 
syenyte  occurs  also  in  the  Frankenstein  Cliff,  five  miles  south  of 
White  Mountain  Notch  ;  also  in  Mount  Chocorua,  N.  H.  ;  in  the  Ar- 
chaean of  Canada,  at  Grenville,  a  red  kind  containing  very  little  quartz, 
and  a  similar  rock  on  Barrow  Island,  St.  Lawrence,  but  containing 
much  quartz  and  little  hornblende.  Syenyte  without  quartz  is  a  rare 
rock  in  Eastern  North  America.  It  occurs  in  Nevada. 

The  name  Syenites  is  used  for  this  rock  by  Pliny,  who  adds  that  it 
was  also  called  "  pyrrhopoecilon"— this  appellation,  meaning  fire-red 
variegated,  referring  to  its  being  brightly  spotted  with  rose-red.  The 
quarries  in  the  vicinity  of  Syene  (the  modern  Assouan),  whence  the 
Egyptians  obtained  this  stone  for  their  obelisks,  columns,  statues, 
sphinxes,  sarcophagi,  and  the  lining  of  their  pyramids,  are  of  great 
extent ;  and  in  one  of  them  there  is  an  unfinished  obelisk  in  its  origi- 
nal position.  They  are  situated  to  the  south  of  Syene,  and  between 
that  place  and  the  island  of  Philoe.  The  rock  consists  chiefly  of  red 
feldspar  and  grayish  quartz,  with  oligoclase,  some  black  hornblende, 
and  a  little  black  mica.  An  analysis  by  Delesse  obtained  Silica 
70 '25,  alumina  16  00,  iron  oxide  with  some  manganese  2 '50,  lime  1'GO, 
expelled  on  ignition  4'65,  magnesia  and  alkalies  by  loss  9  00=100. 
More  remote  from  Syene  the  rock  loses  its  hornblende  and  becomes 
a  granite. 

The  Scotch  syenyte,  so  much  used  for  monuments,  is  quartz-syenyte. 
It  occurs  both  red  and  dark  gray,  and  the  former  is  closely  like  the 
Egyptian  syenyte. 

Werner  applied  the  name  "  syenyte  "  to  the  quartzless  syenyte  of 
Plauen.schen- Grunde,  Saxony,  an  analysis  of  which  is  given  above  (a 
rock  he  afterwards  called  "greenstone").  G.  Rose  used  the  term  for 
the  quartz-syenyte.  Other  German  lithologists  have  followed  Werner, 
calling  the  quartz-syenyte,  hornblende-granite.  It  seems  best  to  draw 


446  DESCRIPTIONS   OF   ROCKS. 

the  line  between  the  mica-bearing  and  the  hornblende-bearing  rocks, 
as  here  done,  and  to  use  the  name  syenyte  for  the  rock  to  which  it  was 
originally  applied,  as  well  as  for  the  quartzless  kinds. 

2.  Syenyte-gneiss. — Like  gneiss  in  aspect  and  schistose 
structure ;    and   also   in   constitution,    except   that   horn- 
blende  replaces  mica.        Occurs   both   with   and   without 
quartz,  though  usually  quartz-bearing.     The  varieties  are 
nearly  the  same  as  under  syenyte.    Metamorphic. 

3.  Hornblende  schist. — A  schistose  rock  consisting  of  horn- 
blende, with   usually  more  or   less  quartz,  but  sometimes 
almost  wholly  hornblende.     Frequently  contains  epidote, 
garnet,  magnetite.    Metamorphic. 

4.  Amphibolyte  or  Hornblendyte,— A  tough,  granular-crys- 
talline rock,  consisting  of  hornblende,  and  hardly  schistose 
in  structure.     Color,  greenish-black  to  black.    Metamorphic. 

A  Glaucophanitic.  variety  consists  chiefly  of  the  blue  soda-hornblende, 
called  glaucophane,  with  usually  some  black  mica  ;  from  Saxony,  Isle 
of  Syra,  New  Caledonia.  A  cTirysolitic  variety  occurs  at  Stony  Point, 
Rockland  Co.,  N.  Y.,  and  on  the  opposite  side  of  the  Hudson  River, 
north  of  Cruger's. 

5.  Actinolyte. — A  tough,   massive  rock  made  chiefly  of 
actinolite.     Grayish  green.     Metamorphic. 

6.  Unakyte. — A  flesh-colored  granitoid  rock  consisting  of 
orthoclase,  quartz,  and  much  yellowish-green  epidote.   From 
the  Unaka  Mountains,  North  Carolina,  and  East  Tennessee. 

II.    CONTAINING  NEPHELITE. 

1.  Zircon-Syenyte. — A  crystalline  granular  rock  consisting 
of  orthoclase,  microcline,  little  hornblende,  crystals  of  zir- 
con, and  some  elseolite. 

2.  Foyayte.— Coarse  crystalline,    granular  to   compact ; 
consists  of  orthoclase,  reddish-brown  nephelite  (eloeolite),  in 
six-sided  prisms,  and  blackish-green  hornblende.     Occurs 
alsoporphyritic,  and  passes  into  an  aphanitic  variety.   From 
Mt.  Foya  and  Picota,  in  the  Province  Algarve,  in  Portugal. 
Ditroyte  (p.  444)  is  related,  but  contains  very  little  horn- 
blende. 

5.   HORNBLENDE  AND  SODA-LIME-FELDSPAR  SERIES. 

I.    NOT  CONTAINING  SAUSSURITE  IN  PLACE  OF  THE 
FELDSPAR  CONSTITUENTS. 

1.  Dioryte.     Quartz-Dioryte.     ( Greenstone  in  part. )— The 
triclinic  feldspar,  one  of  the  acidic  (rich  in  silica)  species, 


KINDS  OF  HOCKS.  447 

albite  or  oligoclase.  Texture  granitoid  to  fine-grained  or 
compact.  Color  often  grayish-white  to  greenish-white  for 
the  coarser  kinds  ;  olive-green  to  blackish-green  for  the 
finer.  Very  tongh.  G.  =2-7-3 '0.  The  quartz-bearing  and 
quartz-less  kinds  constitute  two  sections  having  similar  va- 
rieties. Dark-red,  brownish-red,  and  dark-green  porphy 
ritic  kinds,  compact  in  base,  have  been  called  porpliyryte. 
Metamorphic  and  eruptive. 

VARIETIES. — a.  Granitoid;  granite-like  in  texture,  b.  Compact 
or  fine-grained,  with  the  feldspar  grains  scarcely  distinguishable. 
c.  Porphyritic  ;  the  feldspar  in  crystals  in  a  compact  base.  d.  Slaty  ; 
a  dioryte  slate  or  schist,  usually  chloritic.  e.  Micaceous,  f.  Apha- 
nitic  (or  Aphanite) ;  nearly  flint-like  in  texture. 

An  analysis  of  a  dioryte  of  the  Hartz  afforded  Silica  54'65,  alumina 
15 "72,  iron  sesquioxide  2  '00,  iron  protoxide  6 '26,  manganese  protoxide 
trace,  magnesia  5 '91,  lime  7'83,  potash  3'79,  soda2'90,  water  and  ig- 
nition 1-90  =  100-96. 

The  antique  red  porphyry,  or  "rosso  antico,"  figured  on  page  415, 
is  an  example  of  porphyritic  dioryte.  The  crystals,  according  to  the 
analysis  of  Delesse,  are  oligoclase,  and  have  G.  =2'67,  while  the  base 
has  G.=2'765,  it  consisting  of  an  intimate  mixture  of  oligoclase  and 
hornblende,  with  some  grains  of  iron  oxide.  For  the  whole  mass,  accord- 
ing to  Delesse,  G.  =2.703,  but  after  fusion,  only  2 '486.  Distinct  acicu- 
lar  crystals  of  hornblende  occur  in  it.  The  rock  is  sometimes  a  brec- 
cia, being  made  up  of  angular  fragments,  either  quite  distinct  from  the 
mass  or  else  shading  off  into  it,  but  all  alike  porphyritic.  The  Mt. 
Dokhan,  in  which  it  occurs — "  Porphyrites  mons"  of  Ptolemy — con- 
tains also  red  syenyte  similar  to  that  of  Syene,  and  a  coarse  red  gran- 
ite. The  "porphyrite"  of  Ilfeld,  of  Schonau  in  Bohemia,  and  the 
"  quartz -porphy  rite"  of  Koliwansk  in  the  Altai  are  here  referred. 

Propylyte  and  quartz-propylyte  have 'the  same  constitution.  The 
former  is  the  prevailing  igneous  rock  of  the  Washoe  district  (vicinity 
of  the  Comstock  lode),  in  Nevada ;  it  is  a  grayish-green  rock,  yield- 
ing, on  analysis,  64  to  66  per  cent,  of  silica,  and  containing,  along 
with  oligoclase,  hornblende,  disseminated  in  minute  points,  and  rarely 
alsobiotite  (Zirkel). 

Ophite,  of  the  Pyrenees,  is  greenish  black  dioryte. 

2.  Andesyte.  Quartz- Andesyte. — Contains  the  feldspar  an- 
desite  along  with  hornblende.  As  in  the  preceding,  the 
hornblende'  is  sometimes  changed  to  chlorite.  Quartz-an- 
desyte,  or  Dacyte,  is  a  quartz-bearing  variety.  Both  kinds 
occur  in  the  Washoe  district,  Eruptive.  Also  metamorphie? 

Banatite  and  Tonalite  are  like  quartz-dioryte  in  most  characters, 
but  have  the  feldspar  the  species  andesite.  Each  contains  some  bio- 
tite,  the  latter  much  of  it.  Banatite  is  from  the  Banat,  and  Tonalite 
from  near  Tonal  e,  in  the  Southern  Alps. 

Trachydoleryte  (of  Abich\  a  dark  gray  to  reddish-brown  rock,  some- 
what trachyte-like  in  aspect,  is,  in  part,  near  andesyte,  it  consisting  of 


448  DESCRIPTIONS   OF   HOCKS. 

oligoclase  or  andesite  and  hornblende,  with  G.— 2  73 — 2*80,  and  afford- 
ing 55  to  01  per  cent,  of  silica  ;  it  occurs  in  the  Peak  of  Teneriffe,  on 
Liscanera  I.  near  Stromboli,  and  on  some  parts  of  Etna.  Another  rock 
included  under  this  name,  found  at  Stromboli,  Rocca  Monfina,  and 
Tunguragua  in  Quito,  contains  augite  in  place  of  hornblende,  with 
oligoclase  or  labradorite,  and  is  near  doleryte.  A  third  rock  described 
under  this  name  by  Ludwig  is  augitic  trachyte,  the  feldspar  being 
sanidin.  Trachyte  graduates  into  andesyte,  augite -andesyte,  doleryte, 
as  well  as  granite. 

3.  Labradioryte.  (Labradorite-Dioryte,  Greenstone  in  part.) 
—The  feldspar  one  of  the  basic  (poor  in  silica)  species,  la- 
bradorite or  anorthite.  Texture  usually  fine-grained,  some- 
times crypto-crystalline.  Color  light  grayish-green  to  dark 
olive-green,  blackish-green  or  gray,  and  sometimes  black. 
Very  tough.  G.  =2 -8-3*1.  Often  contains  chlorite  and 
magnetite.  Often  has  associated  with  it  beds  of  serpentine 
or  ophiolyte.  Metamorphic  and  eruptive. 

VABIETIES. — a.  Granular  crystalline,  b.  Compact,  or  fine-grained  ; 
of  dark  green  color  ;  constituent  minerals  not  distinct,  c.  Porphyri- 
tic  ;  the  feldspar  in  whitish  or  greenish- white  crystals  disseminated 
through  a  fine-grained  bass,  making  a  greenish  "porphyry;"  its 
crystals  sometimes  anorthite.  d.  Pyroxcnic ;  containing  some  dissem- 
inated pyroxene,  e.  Magnetitic  ;  containing  magnetite  or  titanic  iron. 
Occurs  in  the  Urals  ;  to  the  west  of  New  Haven,  Conn.,  both  massive 
and  porphyritic  ;  in  Littleton,  N.  H.  A  porphyritic  variety  of  the 
rock  near  New  Baven— a  metamorphic  rock— afforded  Hawes,  Silica 


pact  non-porphyritic  variety  from  the  same  formation,  collected  on 
Stoeckel's  farm,  afforded  Hawes,  Silica  50'36,  alumina  14'57,  iron  ses^ 
quioxide  2'48,  iron  protoxide  8'31,  manganese  protoxide  0'46,  magne- 
sia  7-62,  lime  11-13,  soda  3'04,  potash  0  44,  water  0'78,  titanium  diox- 
ide 1'70,  chromium  oxide  0'78— 100*89  ;  G.=3'04.  The  crystals  of  the 
porphyritic  variety,  according  to  an  imperfect  analysis  by  E.  S.  Dana, 
consist  of  anorthite. 

4.  Corsyte. — A  granitoid  rock,  consisting  chiefly  of  anor- 
thite and  hornblende,  with  some  quartz  and  biotite.     From 
Corsica. 

Teschenite  is  bluish-green,  and  chiefly  consists  of  anor- 
thite, hornblende,  and  augite,  the  hornble  de  sometimes  in 
large  black  prisms  ;  also  contains  analcite.  From  Teschen, 
Austria. 

5.  Isenite. — Contains  a  triclinic  feldspar  and  hornblende, 
with   much   nephelite   and   nosean,  and   some   magnetite. 
From  the  Eisbach  (Isena)  district  in  the  Westerwafd,  West 
Germany. 


KINDS   OF   ROCKS.  449 

II.    SAUSSURITE-BEARING. 

6.  Euphotide.  (Gabbro  in  part.) — A  grayish-white  to  gray- 
ish-green, and  sometimes  olive-green  rock,  very  tough,  having 
G.  =2*9-3 €4.  Consists  of  saussurite  of  whitish  to  greenish 
and  bluish  color,  mixed  either  with  smaragdite  of  emerald- 
green  color,  or  with  green  to  grayish-green  diallage ;  the 
diallage  generally  containing  more  or  less  hornblende,  and 
the  smaragdite,  pyroxene.  The  saussurite  is  commonly  of 
either  the  first  or  second  kind  mentioned  on  page  410  ;  but 
the  distribution  of  these  kinds  is  not  fully  made  out.  Labra- 
dorite  is  rarely  present  locally  in  place  of  the  saussurite. 
Metamorphic. 

VARIETIES. — a.  Diallagic;  diallage  the  chief  foliated  mineral,  b. 
Smaragditic  ;  emerald-green  smaragdite,  the  foliated  mineral,  c.  Mi- 
caceous ;  contains  mica.  d.  Serpentinous ;  contains  some  serpentine — 
a  rock  into  which  it  often  graduates,  e.  Garnetiferous.  f .  /Schistose ; 
especially  so  when  talc  is  present,  g.  Variolitic ;  contains  aphani- 
tic  concretionary  spheroids  of  the  saussurite  mineral,  as  in  the  "  Vario- 
lite  de  la  Durance,"  and  of  Mt.  Genevre,  and  asociated  with  ordinary 
euphotide  ;  for  which  concretions  Delesse  obtained  the  composition 
Silica  56 '12,  alumina  17 '40,  chromium  oxide  0*51,  iron  protoxide  7*79, 
magnesia  3'41,  lime  8'74,  soda  3'72,  potash  0'24,  ignition  1 '93=99-86, 
and  the  specific  gravity  2*923.  The  variety  obtained  at  Orezza  is  the 
Verde  di  Corsica,  of  decorative  art. 

Occurs  near  Lake  Geneva,  in  Savoy  ;  at  Mt.  Genevre  in  Dauphiny, 
near  the  boundary  between  France  and  Italy  ;  at  Allevard,  in  the 
northeastern  part  of  Isere  ;  in  the  valley  of  the  Saas,  north  of  east  of 
the  Monte  Rosa  region  ;  in  the  Grisons  ;  near  Leghorn  and  Bologna  ; 
near  Florence,  at  Mt.  Impruneta,  it  being  the  Oranitone  (page  450) 
of  the  Serpentine  region  ;  on  Corsica,  in  the  Orezza  valley;  in  Silesia  ; 
in  I.  of  Unst.  It  is  often  associated  with  serpentine  ;  and  the  serpen- 
tine and  euphotide  form  beds  in  irregular  masses  among,  and  as  a 
constituent  part  of,  a  series  of  metamorphic  strata,  which  include 
green  chloritic  and  talcose  schists,  limestone  (which,  at  Mt.  Genevre, 
is  of  the  Jurassic  formation),  and  other  rocks.  For  the  Mt.  Genevre 
euphotide,  Delesse  obtained  Silica  45'00,  alumina  and  iron  oxide 
26-83,  lime  8 '49,  magnesia,  soda  and  potash  (by  loss)  13  "90,  water 
and  carbonic  acid  6 '78,  and  for  the  saussurite  the  result  stated  on 
page  410.  The  composition  is  near  that  of  a  labradioryte,  and  the  dif- 
ference in  the  two  rocks  must  have  depended  on  the  different  condi- 
tions attending  crystallization.  The  mixture  of  hornblende  and  py- 
roxene in  either  foliated  constituent,  in  connection  with  their  mutual 
positions  and  structure,  proves  that  part  of  the  hornblende  is  altered 
pyroxene.  The  remark  made  on  page  410  with  reference  to  the  pro- 
duction of  the  saussurite  may  apply  also  to  the  foliated  hornblende, 
and  therefore  to  the  whole  rock. 


450  DESCRIPTIONS   OF   ROCKS. 

6.  PYROXENE  AND  SODA-LIME-FELDSPAR  SERIES. 

1,  Augite-Andesyte. — Contains  the  same  triclinic  feldspar 
as  andesyte,  but  augite  is  present  in  place  of  hornblende. 
Amount  of   silica  obtained  in  analyses  about  55  to  58  per 
cent.    Texture  crystalline-granular  to  aphaiiitic  ;  colors  dark 
gray  to  greenish-black  and  brownish-black.    G.  =  2  '65  -  2  -90. 
Eruptive. 

VARIETIES. — There  are  two  series  :  A.  Ordinary,  that  is,  without 
chrysolite,  or  only  in  traces.  B.  Chrysolitic,  chrysolite  being  in 
disseminated  grains  or  crystals.  Under  each  there  are  varieties  : 
a.  anhydrous ;  b.  hydrous,  or  chloritic,  and  feeble  in  lustre  ;  and 
c.  amygdaloidal,  as  well  as  chloritic.  Again,  each  of  these  varieties 
may  be  porphyritic.  To  the  hydrous  rock,  and  especially  the  chryso- 
litic,  the  term  Melaphyre  is  sometimes  applied. 

Quartz- Augite- Audesyte  is  described  by  Zirkel  as  occurring  in  Pali- 
sade Canon,  in  Nevada  Plateau  ;  it  contains  yellowish-brown  augite, 
some  biotite,  some  grains  of  quartz.  Silica  63  '71  per  cent. 

2.  Gabbro  or  Hyperyte.  (Gabbro,  in  part.). — A  basic  grani- 
toid rock  in  part,  consisting  of  cleavable  labradorite  with  dis- 
seminated pyroxene,  or  a  granular  crystalline  aggregate  of 
the  two  minerals.     The  pyroxene  is  o'ften  foliated,  and  has 
been  improperly  called  hypersthene.     In  place  of  labrador- 
ite, the  feldspar  is  sometimes  andesite,  and  sometimes  anor- 
thite.     Color,  dull  flesh-red  to  brownish-red,  also  dark-gray, 
to  grayish-black.     Tough.     G.=  2  '7-3-1,  varying  with  the 
proportion  of  pyroxene,  which  is  sometimes  small.     Con- 
tains also  magnetite  or  titanic  iron. 

The  name  Gabbro  has  been  applied  to  this  rock ;  also  to  a  coarsely 
granular  igneous  rock,  consisting  chiefly  of  labradorite  and  foliated 
pyroxene,  referred  beyond  to  doleryte  ;  to  euphotide  ;  and,  by  the 
Italians,  formerly  to  serpentine.  Ferber,  in  his  "  Brief e  "  (1773),  says 
(p.  98):  Gabbro  of  Florence  is  the  same  as  the  rock  called  "sachsi- 
schen  Serpentin,  in  Deutschland,"  that  is,  the  serpentine  of  Zoblitz. 
Again,  on  page  330,  he  says  that  Mt.  Impruneta,  seven  Italian  miles 
from  Florence,  consists  of  Gabbro,  or  the  so-called  Saxon  serpentine, 
and  he  alludes  to  the  occurrence  in  it  of  diallage  and  amianthus,  and 
the  presence  also  "  der  sogenannte  Granitone  "  "in  horizontalen 
Sehichten  in  den  Gabbro-Bergen,"  which  sometimes  consisted  "  aus 
weissem  Feldspat,  welcher  grosse  Parallelepipeden  formirte,"  though 
usually  containing  diallage. 

VARIETIES. — a.  Granitoid  ;  the  feldspar  in  distinct  cleavable  grains 
or  masses,  b.  Fe2dspathose  ;  the  pyroxene  feeble  in  amount,  c.  Chry- 
solitic; contains  disseminated  chrysolite,  d.  Anorthitic,  or  Tractolite  ; 
anorthite  replaces  the  labradorite. 

Includes  the  so-called  hypersthenyte  of  the  Adirondacks,  Canada,  and 
Norway.  Occurs  also  in  the  Laramie  Hills,  Colorado,  a  kind  which 
afforded,  on  analysis,  Silica  52-14,  alumina  29'17,  iron  oxide  3  '26,  mag- 
nesia 0-76,  lime  10  81,  soda  3-02,  potash  0'98,  ignition  0'58  =  100 '92. 


KINDS   OF   ROCKS.  451 

3.  Noryte.  Hypersthenyte. — A  rock  consisting  of  labrador- 
ite  or  oligoclase,  with  true  foliated  hypersthene  ;  from  St. 
Paul's,     Labrador,    Hitteroe,    Egersund,    Harzburg;    fine 
grained,  in  Cortlandt,  N.  Y.,  between  Cruger's  and  Peeks- 
kill. 

4.  Doleryte.    (Basalt,   Trap.}—  Chief  constituents,  labra- 
dorite  and  augite,  with  magnetite,  and  sometimes  anortbite. 
Often  porphyritic,  and  the  feldspar  crystals  may  be  anor- 
thite.      Amount   of   silica  yielded   on  analysis  usually  47 
to  52  per  cent.     Texture  crystalline-granular  to  aphanitic; 
and  often,  especially  in  the  latter,  having  glassy  particles 
among  the  crystalline,   or  even   an  unindividualized  base 
or  magma  between  the  crystalline  grains — the  variety  called 
Basalt ;  often  coarse  granular  through  the  body  of  a  dike, 
while  aphanitic  along  its  walls,  and  sometimes  containing 
glassy  portions  in  the  latter  when  not  elsewhere.      Colors 
dark  grayish  to  bluish-black,  greenish-black,  and  brownish- 
black.     6.  =2-75-3-1.     Eruptive  ;  also  metamorphic. 

It  includes  the  larger  part  of  tlie  rock  usually  called  trap,  abundant 
inmost  regions  of  igneous  eruptions  ;  constitutes  the  "trap"  ridges 
of  the  Connecticut  Valley,  the  Palisades  of  New  Jersey,  and  similar 
ridges  in  Nova  Scotia  and  North  Carolina  ;  also  in  the  Lake  Superior 
region,  and  extensive  beds  of  so-called  basaltic  rocks  over  the  Rocky 
Mountain  slopes  west  of  the  Front  Range.  The  rock  of  New  Haven, 
Conn.,  from  West  Rock,  afforded  Silica  51'78,  alumina  14*20,  iron  ses- 
quioxide  3-59,  iron  protoxide  8*25,  manganese  protoxide  0'44,  magne- 
sia 7'63,  lime  10'70,  soda  2 '14,  potash  0'39,  loss  by  ignition  0'63,  phos- 
phorus pentoxide  014=9989;  G.=3  03.  A  hydrous  or  chloritic  variety 
from  Saltonstall's  Ridge,  near  New  Haven,  afforded  Silica  49 '28, 
alumina  15-92,  iron  sesquioxide  1-91,  iron  protoxide  10'20,  manganese 
protoxide  0'37,  magnesia  5 '99,  lime  7'44,  soda  3'40,  potash  0'72,  water 
3-90,  carbon  dioxide  1-14=100'72  ;  G.=2'86. 

VABIETIES. — There  are  two  series  :  A.  Ordinary,  B.  Chrysolitic, 
and  for  the  latter  the  name  Pendotyte  has  been  used.  Each  occurs  : 
a.  anhydrous  ;  b.  hydrous,  or  chloritic,  of  feeble  lustre  ;  c.  amygda- 
loidal,  as  well  as  chloritic  ;  d.  vesicular,  or  scoriaceous,  as  in  doleritic 
or  basaltic  lavas.  JSpilite  is  amygdaloid. 

Again,  each  of  these  varieties  may  be  porphyritic.  Again,  the  augite 
may  be  in  distinct  crystals. 

A  coarse-granular  kind,  having  the  pyroxene  foliated,  is  sometimes 
called  gabbro. 

This  basic  rock,  doleryte,  is  often  called,  also,  basalt,  especially 
when  it  has  an  unindividualized  base  ;  a  specimen  of  this  kind,  from 
Nevada,  is  represented  in  fig.  7,  page  418.  The  name,  anamedte, 
has  been  used  for  an  aphanitic  kind,  but  is  unnecessary. 

Diabase. — The  term  diabase  is  very  often  applied  to  doleryte  older 
than  Tertiary.  It  was  formerly  supposed  that  the  former  differed  from 
the  latter  in  bain"-  chloritic,  and  afterwards  in  never  containing  glassy 
particles  or  an  unindividualized  base  ;  but  neither  distinction  holds. 


452  DESCRIPTIONS   OF   ROCKS. 

The  "antique  green  porphyry,"  or  Porfido  verde  antico,  figured  on 
page  415,  in  fig.  2,  is  a  porphyritic  rock  of  the  composition  of  doleryte, 
the  feldspar  being  labradorite,  and  the  other  chief  constituent,  augite, 
With  also  some  chlorite,  or  viridite,  which  last  is  the  source  of  the 
greenish  color.  It  is  from  the  South  Morea,  between  Lebetsova  and 
Marathonisi.  Delesse  obtained,  from  the  compact  base,  Silica  53*55, 
alumina  19 '84,  iron  protoxide  7'35,  manganese  protoxide  0'85,  lime 
8*02,  soda  and  potash  7'9o,  water  2'67.  In  view  of  its  firmness,  and 
its  contrast  in  this  respect  with  most  chloritic  doleryte,  it  may  be 
queried  whether  the  rock  is  not  a  metamorphic  doleryte  (metadoleryte). 
It  closely  resembles  the  porphyritic  labradioryte  from  the  vicinity  of 
New  Haven,  Conn,  (which  is  chloritic  and  metamorphic),  though  differ- 
ing from  it  in  containing  pyroxene  instead  of  hornblende.  A  similar 
porphyry  is  reported  from  Elbingerode  in  the  Hartz,  Belfahy  in  the 
Vosges,  and  Barnetjern  near  Christiania  in  Norway. 

5.  Eucryte. — A  doleryte-like  rock  consisting  chiefly  of  an- 
orthite  and  augite.     Occurs  compact,  and  as  a  lava.     From 
Elfdalen,  Norway. 

6.  Amphigenyte.    (Leucitopliyre.} — Contains    augite,  like 
doleryte,  but  leucite  (called  sometimes  amphigene)  replaces 
the  feldspar.     Dark  gray,  fine-grained,  and  more  or  less  cel- 
lular to  scoriaceous.     G-.— 2-7-2-9.     The  leucite  is  dissemi- 
nated in   grains  or  in  24-faced  crystals.     Constitutes  the 
lavas  of  Vesuvius  and  some  other  regions.     Accessory  min- 
erals, nephelite,  biotite,  chrysolite,  sodalite,  sanadin,  labra- 
dorite and  nosean. 

Hauynophyre  is  an  amphigenyte  from  Vulture,  near  Melfi,  in  which 
hauynite  replaces  much  of  the  leucite. 

7.  Nephelinyte.    (Nepheline-doleryte. ) — Contains  augite, 
like  doleryte,  but  nephelite  replaces  the  feldspar,  or  the  larger 
part  of  it.     Crystalline-granular  ;    ash-gray  to   dark   gray. 
The  nephelite  is  partly  in  distinct  crystals. 

8.  Tachylyte.   Hyalomelan. — Blackish  glass,  or  pitchstone, 
•made  in  connection  with  augitic  igneous  rocks  or  lavas  ; 
the  former  affords  on  analysis  49  per  cent,  of  silica,  and  the 
latter  55. 

This  Doleryte-pitcJistone  may  be  porphyritic,  or  contain  small  grains 
of  augite,  or  of  chrysolite. 

7.  PYROXENE,  GARNET,  EPIDOTE,  AND  CHRYSOLITE  ROCKS. 
CONTAINING  LITTLE  OR  NO  FELDSPAR. 

1.  Pyroxenyte. — Coarse  or   fine  granular  pyroxene  rock. 
Sometimes  chrysolitic,  a  variety  which  occurs  with  chryso- 
litic  hornblendyte  at  the  localities  mentioned  on  p.  446. 

2.  Garnetyte,  or  Garnet  Rock, — A  yellowish-white  to  green- 


KINDS   OF   ROCKS.  453 

isli- white,  tough  rock,  consisting  of  an  alumina-lime  garnet. 
G.=3-39-3-49.  From  St.  Francis,  Canada.  The  superior 
yellow  iiovaculite  or  whetstone,  of  Vieil  Salm,  Belgium,  has 
the  constitution,  according  to  A.  Kenard,  of  a  manganesian 
garnet.  Metamorphic. 

3.  Eclogyte. — Compact  and  tough.     Consists  of  granular 
garnet  and  hornblende,  with  grass-green  smaragdite.     G.  = 
3-2-3-5.     A  related  rock  consists  of  reddish  or  brownish- 
yellow  garnet,  and  black  or  greenish-black  hornblende,  with 
often  some  magnetite.     Metamorphic. 

4.  Epidosyte. — Pale  green  to  pistachio-green.     Consists  of 
epidote  mixed  with  quartz.     Metamorphic. 

5.  Eulysyte. — Fine-granular,  consisting  of  chrysolite  with 
a  diallage-like  mineral  and  garnet.     Forms  a  bed  in  gneiss 
near  Tunaberg,  Sweden. 

6.  Chrysolyte,  or  Chrysolite-Reck. — Yellowish  to  pale  olive- 
green,   granular  ;    consisting   almost  wholly   of  chrysolite. 
G-.  =r  3-3-1;  H.  —  5-5-6.     Abundant  in  Macon  County,  N. 
Carolina ;  in  part  changed  to  serpentine.     Metamorphic. 

Dunyte  is  yellowish-green  ;  granular,  and  consists  of  chrysolite,  with 
some  chromite.  From  Mount  Dun,  New  Zealand.  Eruptive. 

7.  Lherzolyte. — Greenish-gray ;  crystalline  granular.  Con- 
sists of  chrysolite,  enstatite,  whitish  pyroxene,  with  chrome- 
spinel  and  sometimes  garnet.     From  Lake  Lherz,  etc.     Is 
it  metamorphic  ? 

8.  Picryte.— Blackish-green  to  brownish-red ;  crystalline- 
granular.     Consists  of  chrysolite,  with  augite  sometimes  in 
crystals.     Graduates  into  chrysolitic  doleryte.  _ 

9.  Limburgyte. — A  semi-glassy  rock,  consisting  of  chryso- 
lite and  augite,  with  some  magnetite.     It  is  occasionally 
amygdaloidal.     Affords  on  analysis  43  per  cent,  of  silica. 

8.  HYDROUS  MAGNESIAN  AND  ALUMINOUS  ROCKS. 

Contain  one  or  more  of  the  hydrous  magnesian  minerals, 
chlorite,  talc,  serpentine,  or  the  related  hydrous  aluminous 
mineral,  pyrophyllite.  The  fine-grained  kinds  are  more  or 
less  greasy  to  the  touch  ;  and  some  of  them  resemble  the 
hydromica  slates. 

1.  Chlorite  Schist.— Schistose  ;  color  dark  green  to  grayish- 
green  and  greenish-black  ;  but  little,  if  any,  greasy  to  the 
touch.  Consists  of  chlorite,  with  usually  some  quartz  and 


454  DESCRIPTIONS   OF   ROCKS. 

feldspar  intimately  blended,  and  often  contains  crystals 
(usually  octahedrons)  of  magnetite,  and  sometimes  chlorite 
in  distinct  scales  or  concretions.  Metamorphic. 

VARIETIES. — a.  Ordinary,  b.  HornUendic  ;  the  hornblende  ingrains 
or  needles,  c.  Magnetitic.  d.  Tourmalmic.  e.  Garnetiferous.  f.  Pyr- 
oxenic.  g.  Staurolitic.  h.  Epidotic.  Graduates  into  argillyte. 

2.  Chlorite-Argillyte. — An  argillyte  or  phyllyte  consist- 
ing largely  of  chlorite.     Metamorphic. 

3.  Talcose  Schist. — A  slate  or  schist  consisting  chiefly  of 
talc.     Not  common,  except  in  local  beds,  most  of  the  so- 
called  "talcose  slate"  being  hydromica  schist  (p.  440). 

4.  Steatyte,   Soapstpne  (p.  55).— Consists  of  talc.     Mas- 
sive, more  or  less  schistose  ;  granular  to  aphanitic.     Color, 
gray  to  grayish -green  and  white.     Feels  very  soapy.    Easily 
cut  with  a  knife.     Metamorphic. 

VARIETIES. — a.  Coarse-granular,  and  massive  or  somewhat  schis- 
tose, b.  Fine-granular;  "French  chalk."  c.  Aphanitic,  or  Rens- 
selaerite;  of  grayish-white,  greenish,  brownish  to  black  colors,  from 
St.  Lawrence  County,  N.  Y. ,  and  Grenville,  Canada. 

5.  Serpentine. — Aphanitic   or  hardly  granular ;  of  dark- 
green  to  greenish-black  color,  easily  scratched  with  a  knife, 
and  often  a  little  greasy  to  the  feel  on  a  smooth  surface. 
Although  generally  dark  green,  it  is  sometimes  pale  grayish 
and  yellowish-green,  and  mottled.     Metamorphic. 

Varieties. — a.  Noble;  oil -green  and  translucent,  b.  Common;  opaque, 
and  of  various  colors,  c.  Schistose,  d.  Diallagic ;  contains  green  or 
metalloidal  diallage.  e.  Chromiferous;  contains  chromite,  a  chromium 
ore  belonging  to  serpentine  regions,  f .  B<tstitic  ;  contains  bastite  or 
enstatite.  g.  Garnetiferous ;  contains  garnet,  as  at  Zoblitz.  h.  Chry- 
solitic  ;  contains  chrysolite,  i.  Brecciated ;  consists  of  united  frag- 
ments. (See  also  page  308.)  Serpentine  has  been  made  by  the  altera- 
tion of  chrysolite  beds,  and  of  chondrodite  and  other  magnesian  sili- 
cates. A  rock  consisting  of  serpentine  and  saussurite  is  true  Gabbro. 

6.  Ophiolyte  (Verd- Antique  Marble). — A  mixture  of  ser- 
pentine with  limestone,   dolomite,   or  magnesite,  having  a 
mottled  green  color.     Often  contains  disseminated  magne- 
tite or  chromite.    Metamorphic. 

VARIETIES. — a.  Calcareous;  the  associated  carbonate  being  cal cite, 
b.  Dolomitic  ;  the  associated  carbonate,  dolomite,  c.  Magnesitic  ;  the 
associated  carbonate,  magnesite.  Either  of  these  kinds  may  contain 
chromite  or  magnetite.  Handsome  verd-antique  marble  has  been  ob- 
tained near  New  Haven  and  Milford,  Conn.  A  beautiful  variety,  hav- 
ing pure  serpentine  disseminated  in  grains  or  spots  through  a  whitish 
calcite,  occurs  at  Port  Henry,  Essex  County,  N.  Y.,  and  is  worked. 


KINDS   OF  ROCKS.  455 

7.  Pyrophyllyte  and  Pyrophyllite  Slate.— Lil;e  the  preced- 
ing in  appearance  and  soapy  feel,  but  having  the  composi- 
tion of  pyrophyllite  (p.  306).  The  color  is  white  and  gray 
or  greenish  white.  Occurs  in  North  Carolina.  One  of  the 
varieties  from  the  Deep  River  region  is  used  for  slate  pen- 
cils. Metamorphic. 


9.  IRON-ORE  ROCKS. 

1.  Hematyte.  (Specular  Iron  Ore).  —  Hematite  (p.  176),  in 
metamorphic  beds.  Color  iron  gray,  and  lustre  bright  me- 
tallic, but  varying  to  red  and  jaspery.  Has  the  hardness  of 
crystallized  hematite  and  its  red  streak.  Constitutes  beds 
of  great  thickness  in  Archaean  regions  and  thinner  beds  in 
formations  of  later  geological  age  ;  alternates  with  horn- 
blendic,  chloritic,  micaceous,  and  gneissoid,  and  sometimes 
calcareous  rocks,  and  often  contains  siliceous  or  jaspery 
layers. 

VARIETIES.  —  a.  Iron-gray  ;  the  ordinary  massive  kind.  b.  Red; 
resembling  a  hard  red  jasper,  into  which  it  sometimes  passes,  c.  Con- 
taining martite;  the  octahedral  crystals  of  martite  having  originally 
been  magnetite,  and  showing  that  they  are  changed  to  hematite  by 
their  red  streak,  d.  Foliated  ;  sometimes  called  micaceous  iron  ore, 
in  allusion  to  the  foliation,  e.  Epidotic. 

In  large  beds  in  the  Archaean  of  Canada,  St.  Lawrence  Co.,  N.  Y., 
at  Marquette,  Northern  Michigan,  Missouri.  At  Nictaux,  in  Nova 
Scotia,  in  semi-metamorphic  fossilif  erous  Devonian  there  is  a  bed  six 
feet  thick. 


2.  Itabyryte.  —  A  mica  schist  consisting  largely  of 
tite  in  laminae  of  bright  metallic  lustre. 

3.  Magnetyte.  (Magnetic  Iron  Ore).  —  Magnetite  (p.  178), 
in  metamorphic  beds.     Color  iron  gray  to   grayish  black, 
and  lustre  metallic  ;  never  bright  red.     Strongly  attracted 
by  the  magnet,  and  hence  often  separated  from  the  gangue, 
after  crushing  it,  by  means  of  large  electro-magnets.     Con- 
stitutes, like  hematite,  thick  beds  in  Archaean  regions,  and 
thinner  in  rocks  of  other  periods. 

VARIETIES.  —  a.  Massive,  b.  Granular,  c.  Epidotic.  d.  Horriblendic. 
e.  Chloritic.  f.  Titanic,  g.  Chondroditic  ;  as  near  Brewster,  N.  Y., 
where  chondrodito  is  the  "  gangue"  of  the  ore. 

Metamorphic  magnetite  constitutes  thick  beds  in  the  Archaean  of 
Canada,  Northern  New  York,  Orange  Co.,  N.  Y.,  Sussex  Co.,  N.  J., 
and  occurs  also  in  Virginia,  east  of  the  Blue  Ridge,  in 


456  .  DESCRIPTIONS   OF   ROCKS. 

Essex,  and  Nelson  counties,  and  elsewhere.  Forms  a  small  bed  in  the 
Upper  Silurian  of  Bernardston,  Mass.,  and  in  Devonian,  at  Moose  River, 
in  Nova  Scotia. 

4.  Menaccanyte.   (Titanic  Iron  Ore). — Resembles  massive 
hematite,  but  consists  chiefly  of  titanic  iron  (p.  178).     Oc- 
curs in  the  Archaean  of  Canada,  as  in  the  parish  of  St.  Ur- 
bain,  at  Bay  St.  Paul,  where  the  bed  is  ninety  feet  thick. 

5.  Franklinyte. — Resembles  massive  magnetite,  but  con- 
sists of  franklinite  (p.  179),  which  differs  from  magnetite  in 
containing  more  or  less  zinc  and  manganese. 

Occurs  at  Mine  Hill,  in  Hamburg,  N.  J.,  and  also  at  Stirling  Hill,  in 
the  same  region,  constituting  a  bed  of  great  thickness.  It  is  mixed 
•with  zinc  ores,  zincite  and  willemite,  besides  other  minerals,  and  asso- 
ciated with  granular  limestone,  in  an  Archaean  region  of  hornblendic 
and  gneissoid  rocks. 

For  non-metamorphic  kinds  of  iron  ores,  see  under  HEMATITE 
(p.  176),  LIMONITE  (p.  181),  and  SIDERITE  (p.  185).  Beds  of  magne- 
tite occur  only  in  metamorphic  region*. 


GENERAL  INDEX. 


Acadialite,  300. 

Acanthite,  118. 

Acmite,  247. 

Actinolite,  249. 

Actinolyte,  446. 

Adamantine  spar,  193. 

Adamite,  156. 

Adularia,  278. 

JSgirine,  JSgyrite,  247. 

^Eschynite,  202,  260. 

Agalmatolite,  306,  312. 

Agate,  236. 

Aikinite,  136,  149. 

Akanthit,  v.  Acanthite. 

Alabandite,  188. 

Alabaster,  210. 

Albertite,  326. 

Albite,  277. 

Alexandrite,  196. 

Algodonite,  135. 

Alipite,  168. 

Alisonite,  near  Covellite,  133. 

Allanite,  203,  263. 

Allemontite,  101. 

Allopalladium,  127. 

Allophane,  296. 

Allophite,  318. 

Alluaudite,  191. 

Alluvium,  429. 

Almandin,  Almandite,  257. 

Altaite,  149. 

Alum,  native,  198. 

Alum  shale,  428, 

Alum  stone,  198. 

Aluminite,  199. 

Aluminum,  Compounds  of,  192. 

fluorides,  197. 
Alunite,  198. 
Alunogen,  197. 
Amalgam,  117,  128. 
Amazonstone,  278. 
20 


Amber,  325. 
Amblygonite,  44,  199. 
Ambrite,  325. 
Amethyst,  235,  239. 

Oriental,  193. 
Amianthus,  250,  308. 
Ammonium  alum,  198,  231. 
Ammonium,  Salts  of,  230. 
Amphibole,  249. 
Arnphibolyte,  446. 
Amphigene,  271. 
Amphigenyte,  452. 
Amygdaloid,  418,  451. 
Analcite,  Analcime,  69,  299. 
Anatase,  451. 
Anamesite,  163. 
Ancramite,  159. 
Andalusite,  284. 
Andesine,  Andesite,  276. 
Andesyte,  447. 
Andradite,  258. 
Andre  wsite,  185. 
Anglesite,  150. 
Anhydrite,  211. 
Ankerite,  186,  220. 
Annabergite=Nickel  arsenate. 
Annite,  266. 
Anorthite,  44,  275. 
Anthophyllite,  252. 
Anthracite,  327. 
Anthraconite,  217. 
Antigorite,  308. 
Antillite,  309. 
Antimonate,  Calcium,  214. 

Copper  139. 

Lead,  152. 
Antimonial  copper  ores,  135,  136. 

lead  ores,  149. 

nickel  ores,  166. 

silver  ores,  119,  120. 
Antimonite, 

457 


458 


GENERAL   INDEX. 


Antimony,  Native,  100. 

glance,  ?>.  Stibnite. 
Apatite,  46,  48,  49,  67,  213. 
Aphanesite,  139. 
Aphrodite,  307. 
Aphrosiderite,  319. 
Aphthitalite,  227. 
Apjohnife;  198. 
Aplome,  258. 
Apophyllite,  294. 
Aquamarine,  252. 
Aragonite,  218. 
Aragotite,  324. 
Arcanite,  227. 
Arfvedsonite,  252. 
Argentine,  121,  216". 
Argentite,  117,  121. 
Argillyle,  428. 
Arkansite,  163. 
Arkose,  436. 
Arksutite,  197. 
Arquerite,  117. 
Arragonite,  218.. 
Arsenate,  Calcium,  214. 

Cobalt,  167,  168. 

Copper,  139. 

Iron,  185. 

Lead,  152. 

Uranium,  170,  171. 

Zinc,  156. 

Arsenic,  Native,  98. 
Arsenic  group,  98. 

sulphide,  99. 

White,  99. 
Arsenical  antimony,  101. 

cobalt,  165r  166, 

iron  ore,  175, 176. 

lead  ores,  149. 

nickel,  165, 166. 
Arsenide,  Cobakr  165^  166i 

Copper,  135. 

Iron,  175,  176. 

Manganese,  188. 

Nickel,  165, 166. 
Arsenioaiderite,  185. 
Arsenolite.  99. 
Arsenopyrite,  175. 
Asbestua,  246,  250. 

Blue,  -0.  Crocidolite. 
Asbolan,  Asbolite,  167. 
Asmanite,  241. 
Asparagus-stone,  213. 
Aspasiolite,  315. 


Asphaltum,  326. 
Aspidolite,  266. 
Astrakanite,  v.  Blodite. 
Astrophyllite,  266. 
Atacamite,  136. 
Atopite,  214. 
Auerbachite,  260. 
Augite,  245. 

andesyte,  450. 
Augitic  trachyte,  448. 
Aurichalcite,  141,  157. 
Auriferous  pyrite,  173. 
Auripigmentum,  99. 
Automolite,  196. 
Autunite,  170. 
Aventurine  quartz,  235. 

feldspar,  279. 
Axinite,  44,  264. 
Azurite,  141. 

Babingtonite,  247. 
Bagrationite,  ID.  Allanite. 
Baltirnorite,  308. 
Banatite,  447. 
Barite,  220. 

Barium,  Compounds  of,  220. 
Barytes,  220. 
Barytocalcite,  222. 
Basalt,  451. 
Basanite,  237. 
Bastite,  309. 
Bathvillite,  325. 
Beaumontite,  304. 
Bechilite,  212. 
Benzole,  324. 
Berthierite,  176. 
Beryl,  46,  252. 
Berzelianite,  135. 
Beyrichite,  165. 
Bieberite,  168. 
Biharite,  312. 
Bindheimite,  152. 
Binnite,  136. 
Biotite,  266. 
Bismite,  102. 
Bismuth,  101. 

Bismuth  glance,  «.  Bismuthinitc. 
Bismuth  ores,  102. 
carbonate,  102. 
Bismuth  nickel,  166. 
Bismuth  silver,  116. 
Bismuthinite,  102. 
Bismutite= Bismuth  carbonate. 


GENERAL    INDEX. 


459 


Bismutoferrite,  256. 
Bitter  spar,  v.  Dolomite. 
Bitumen,  326. 

Elastic,  324. 
Bituminous  coal,  327. 
Bituminous  shale,  428. 
Black  cobalt,  167. 

copper,  137. 

jack,  155. 

lead,  107. 

silver,  119. 
Blende,  154. 
Blodite,  206,  227. 
Blomstraudite,  170. 
Bloodstone,  237. 
Blue  iron  earth,  185. 

copper,  133. 

vitriol,  137. 
Bodenite,  263. 
Bog  iron  ore,  181. 

manganese,  190. 
Bole,  Halloysite,  312. 
Boltonite,  256. 
Boracic  acid,  97. 
Boracite,  206. 
Borate,  Ammonium,  231. 

Calcium,  212. 

Hydrogen,  98. 

Iron,  182. 

Magnesium,  206. 

Sodium,  212,  227. 
Borax,  227. 
Bornite,  134 
Borocalcite,  212. 
Boronatrocalcite,  212. 
Boron  group,  97. 
Bort,  103. 
Bosjemanite,  198. 
Botryogen,  182. 
Botryolite,  289. 
Boulangerite,  149. 
Bournonite,  136. 
Boussingaultite,  231. 
Bowenite,  309. 
Bragite,  260. 
Branchite,  324. 
Brandisite,  320. 
Brass,  composition  of,  144. 
Braunite,  189. 
Bravaisite,  302. 
Breccia,  426. 
Bredbergite,  258. 
Breislakite,  v.  Pyroxene. 


Breithauptite,  166. 

Breunerite  =  Ferriferous    Magne- 

site. 

Brewsterite,  304. 
Brittle  silver  ore,  119. 
Brochantite,  138. 
Bromargyrite,  121. 
Bromic  silver,  121. 
Bromlite,  222. 
Bromyrite,  121. 
Brongniardite,  120,  149. 
Bronze,  144. 
Bronzite,  244. 
Brookite,  163. 
Brown  coal,  327. 

hematite,  181. 

iron  ore,  181. 

ochre,  181. 

spar,  219. 

stone,  427. 
Brucite,  204. 
Brushite,  214. 
Bucholzite,  285. 
Bucklandite,  262. 
Buhrstone,  437. 
Buratite,  141,  157. 

Cacholong,  240. 

Cacoxenite,  Cacoxene,  185. 

Cadmium,  Ores  of,  159. 

Cairngorm  stone,  235. 

Caking  coal,  327. 

Calaite,  v.  Callaite. 

Calamine,  157,  S96. 

Calaverite,  115. 

Calcite,  49,  50,  215. 

Calcium,  Compounds  of,  207. 

Calc  spar,  215. 

Caledonite,  149. 

Callainite,  200. 

Callais,  Callaite,  200. 

Calomel,  129. 

Canaanite= White  Pyroxene,  245. 

Cancrinite,  270. 

Cannel  coal,  327. 

Cantonite,  near  Covellite,  133. 

Caoutchouc,  Mineral,  324. 

Capillary  pyrites,  164. 

Carbonaceous  shale,  428. 

Carbonado,  103. 

Carbonate,  Ammonium,  231. 

Barium,  221. 

Calcium,  215,  218,  219. 


460 


GENERAL    INDEX. 


Carbonate,  Bismuth,  102. 

Cerium,  203. 

Copper,  140,  141. 

Iron,  185. 

Lanthanum,  203. 

Lead,  152. 

Magnesium,  207,  219, 

Manganese,  191. 

Sodium,  229,  230. 

Strontium,  223. 

Uranium,  171. 

Yttrium,  203. 

Zinc,  156. 

Carbonic  acid,  108,  423. 
Carburetted  hydrogen,  321. 
Carnallite,  205. 
Carnelian,  236. 
Carpholite,  296. 
Carrara  marble,  433. 
Cassiterite,  160. 
Castor,  Castorite,  249. 
Catapleiite,  295. 
Cataspilite,  312. 
Catlinite,  429. 
Cat's-eye,  236. 
Celadonite,  307. 
Celestite,  Celestine,  222. 
Cerargyrite,  120,  121. 
Cerite,  298. 
Cerium  ores,  201. 
Cerolite,  309. 
Cerussite,  152. 
Cervantite,  101. 
Chabazite,  800. 
Chalcanthite,  137. 
Chalcedony,  235. 
Chalcocito,  133. 
Chalcodito,  307. 
Chalcolite,  170. 
Chalcomorphite,  296. 
Chalcophanite,  189. 
Chalcophyllite,  139. 
Chalcopyrite,  133. 
Chalcosiderite,  185. 
Chalcosine,  133. 
Chalcostibite,  136. 
Chalcotrichite= Capillary  Cuprite, 

136. 

Chalk,  215,  432. 
Chalybite  —  Siderite. 
Chathamite,  <y.  Chloanthite. 
Chert,  287,  436. 
Chessy  Copper,  v.  Azurite. 


Chesterlite,  v.  Microcline. 
Chiastolite,  285. 
Childrenite,  200. 
Chiolite,  197. 
Chloanthite,  165. 
Chlor -apatite,  213. 
Chlorastrolite,  296. 
Chloride,  Ammonium,  230. 

Copper,  136. 

Lead,  149,  153. 

Magnesium,  205. 

Mercury,  129. 

Potassium,  224. 

Silver,  120. 

Sodium,  224. 
Chlorite  argillyte,  454 

Group,  316. 

schist,  453. 
Chloritoid,  320. 
Chlormagnesite,  205. 
Chloropal,  307. 
Chlorophaeite,  318. 
Chlorophane,  208. 
Chlorophyllite,  265,  315. 
Chlorotile,  139. 
Chodneffite,  197. 
Chondrodite,  281. 
Chonicrite,  317. 
Chromate,  Lead,  150, 151. 
Chrome  yellow,  151. 
Chromic  iron,  180. 
Chromite,  180. 
Chrysoberyl,  196. 
Chrysocolla,  142,  295. 
Chrysolite,  255. 

rock,  453. 
Chrysolyte,  453. 
Chrysoprase,  236. 
Chrysotile,  308. 
Churchite,  203. 
Cimolite,  307. 
Cinnabar,  128. 
Cinnamon  stone,  257. 
Cipolin  marble,  434. 
Citrine,  235. 
Claudetite,  100. 
Clausthalite,  149. 
Clay,  429. 

iron-stone,  177, 181,  186 

slate,  428. 
Cleavelandite,  278. 
Cleiophane,  155. 
Cleveite,  170. 


GENERAL   INDEX. 


461 


Clingmanite,  319. 
Clinkstone,  444. 
Clinochlore,  319. 
Clinoclasite,  139. 
Clinohumite,  281. 
Clintonite,  v.  Seybertite. 
Coal,  Mineral,  327. 

Brown,  328. 

Cannel,  327. 
Cobalt  bloom,  167. 

glance,  165. 

Ores  of,  163. 

pyrites,  164. 

vitriol,  168. 

Cobaltite,  Cobaltine,  165. 
Coccolite,  246. 
Coke,  328. 
Collyrite,  296. 
Colophonite,  258. 
Coloradoite,  129. 
Colorados,  121. 
Columbates,    170,    183,   202, 

214. 

Columbite,  183. 
Columbium,  184. 
Comptonite,  298. 
Conglomerate,  426. 
Connellite,  47  (f.  11),  138. 
Cookeite,  314. 
Copal,  Fossil. 
Copaline,  Copalite,  325. 
Copiapite,  182. 
Copper,  Native,  131. 

froth,  139. 

glance,  132. 

Gray,  135. 

mica,  130. 

nickel,  166. 

Ores  of,  130. 

pyrites,  133,  134 

vitriol,  137. 
Copperas,  182. 
Coprolites,  213. 
Coquimbite,  182. 
Cordierite,  264. 
Corneous  lead,  153. 
Cornwallite,  139. 
Corsyte,  448. 
Corundellite,  319. 
Corundophilite,  319. 
Corundum,  192. 
Cossaite,  314. 
Cotunnite,  149. 


203, 


Covellite,  Covelline,  133. 
Crednerite=Cu  ,Mn2O6. 
Crichtonite,  ».  Menaccanite. 
Crocidolite,  252. 
Crocoite,  Crocoisite,  150. 
Cronstedtite,  319. 
Crookesite,  135. 
Cryolite,  197. 
Cryophyllite,  268. 
Cryptolite,  203. 
Cryptomorphite,  212. 
Cubanite,  134. 
Cube  ore,  185. 
Cubic  nitre,  229. 
Culsageeite,  317. 
Cummingtonite,  250. 
Cuprite,  136. 
Cuproscheelite,  212. 
Cuprotungstite,  138. 
Cyanite,  286. 
Cyanotrichite,  138. 
Cymatolite,  248. 
Cyprine,  261. 

Daleminzite,  118. 

Damourite,  313,  441. 

Danaite,  175. 

Danalite,  256. 

Danburite,  264. 

Datholite,  Datolite,  289. 

Daubreelite,  180. 

Daubreite,— Bismuth  oxichloride, 

Dawsonite,  201. 

Dechenite=Lead  vanadate. 

Degeroite,  315. 

Delessite,  318. 

Delvauxite,  v.  Dufreni'je. 

Dendrites,  59. 

Derbyshire  spar,  209. 

Descloizite, 

Desmine,  303. 

Deweylite,  309. 

Diabantachronyn,  318. 

Diabantite,  318. 

Diabase,  452. 

Diallage,  Green,  246. 

Diallogite,  t>.  Rhodochrosite. 

Diamond,  103. 

Dianite,  u.  Columbite. 

Diaphorite  =  Trimetric  Frelesleb. 

enite. 
Diaspore,  194. 
Dichroite,  264 


4G2 


GENERAL    INDEX. 


Bickinsonite,  191. 
Didymium  ores,  201,  203. 
Bihydrite,  139. 
Binite,  324. 
Biopside,  246. 
Dioptase,  141,  256,  295. 
Bioryte,  446. 
Biphanite,  319. 
Bipyre,  209. 
Bisterrite,  320. 
Bisthene,  286. 
Bitroyte,  444. 
Bog-tooth  Spar,  215. 
Bolerophanite,  138. 
Boleryte,  451. 

pitchstone,  452. 
Bolomite,  207,  219. 
Bolomyte,  43'3,  434. 
Bomeykite,  135. 
Bomyte,  443. 
Breelite,  221. 
Bry-bone,  158,  364. 
Budleyite,  320. 
Bufrenite,  185. 
Bufrenoysite,  149. 
Bunyte,  453. 
Burangite,  199. 
Butch  white,  221. 
Bysanalyte,  202,  214. 
Byscrasite,  119. 
Bysluite,  196. 
Bysodile,  325. 
Bysyntribite,  312. 

Earthy  cobalt,  167. 
Ecdemite,  152. 
Eclogyte,  453. 
Edelforsite,  245. 
Edenite,  251. 
Edingtonite,  296. 
Edwardsite,  •».  Monazite. 
Ehlite,  139. 
Ekebergite,  269. 
Ekmannite,  316. 
Elseolite,  269. 
Elaterite,  324. 
Electro-silicon  430. 
Electrum,  110 
Eliasite,  170. 
Embolite,  121. 

Embrithite,  v.  Boulangerite. 
Emerald,  252. 
Oriental,  193. 


Emerald,  nickel,  168. 

Emery,  193. 

Emerylite,  319. 

Emplectite,  136. 

Enargite,  136. 

Enceladite,  «.  Warwickite. 

Eustatite,  244. 

Enysite,  138. 

Eosite,  near  Vanadinite. 

Eosphorite,  200. 

Epichlorite,  316. 

Epidosyte,  453. 

Epidote,  262. 

Epistilbite,  302,  304. 

Epsom  salt,  Epsomite,  205. 

Erbium  ores,  201. 

Erdmannite,  296. 

Erinite,  139. 

Erubescite,  134. 

Erythrite,  167. 

Esmarkite,  265,  315. 

Eucairite,  118,  135. 

Euchroite,  139. 

Euclase,  288. 

Eucolite,  254. 

Eucrasite,  296. 

Eucryte,  452. 

Eudyalite,  Eudialyte,  254,  260. 

Eudnophite,  300. 

Eukairite,  V.  Eucairite. 

Eulysyte,  453. 

Eulytite,  Eulytine,  102,  256. 

Euosmite,  325. 

Euphotide,  449. 

Euphyllite,  314. 

Eupyrchroite,  213. 

Euralite,  318. 

Euryte,  442. 

Euxenite,  202. 

Fahlerz,  135. 
Fahlunite,  265,  314. 
Fairfieldite,  191. 
Fassaite,  246. 
Faujasite,  300. 
Fayalite,  256. 

Feather  ore,  v.  Jamesonite. 
Feldspar  Group,  272. 
Felsite,  280. 
Felspar,  v.  Feldspar. 
Felsyte,  442. 
Fergusonite,  202,  260. 
Fibrofemte,  182. 


GENERAL    INDEX. 


463 


Fibrolite,  285. 
Fichtelite,  324. 
Fiorite,  240. 
Fioryte,  437. 

Fireblende  v.  Pyrostilpnite. 
Fire-marble,  431. 
Fire-opal,  239. 
Fischerite,  200, 
Flint,  237. 
Float-stone,  241. 
Flos  ferri,  218. 
Flueliite,  197. 
Fluidal  texture,  418. 
Fluocerine,  202. 
Fluocerite,  202. 
Fluor-apatite,  213. 
Fluor,  Fluorite,  208. 
Fluor  spar,  208. 
Fluorides,  Aluminum,  197. 

Calcium,  208. 
Foliated  tellurium,  149. 
Fontainebleau  limestone,  216. 
Foresite,  304. 
Forsterite,  255. 
Fowlerite,  247. 
Foyayte,  446. 
Franklinite,  158,  179,  456. 
Free-stone,  427. 
Freibergite  — Argentiferous  Tetra- 

hedrite. 

Freieslebenite,  120,  121,  149. 
Frenzelite,  102. 
Friedelite,  256. 

Gabbro,  449,  450,  454 

Gadolin,  Gadolinite,  203,  263. 

Gagates,  328. 

Gahnite,  196. 

Galena,  Galenite,  121,  145. 

Galmei,  157. 

Ganomalite,  153. 

Garnet,  256. 

rock,  452.      ; 
Garnetyte,  452. 
Garnierite,  168. 
Gastaldite,  252. 
Gay-Lussite,  230. 
Gearksutite,  197. 
Gehlenite,  284. 
Genthite,  168,  309. 
Geocerite,  325. 
Geocronite,  149. 
Geomyricite,  325. 


Gersdorffite,  166. 

Geyserite,  240,  437. 

Gibbsite,  194. 

Gieseckite,  270,  313. 

Gigantolite,  265  315. 

Gillingite,  316. 

Girasol,  239. 

Gismondite,  Gismondine,  296. 

Glagerite,  312. 

Glaserite,  v.  Arcanite, 

Glass,  416. 

Glauber  salt,  41,  68,  226. 

Glanberite,  227. 

Glaucodot=Cobaltic  Arsenopyrite. 

Glaucolite,  269. 

Glauconite,  307,  429. 

Glaucophane,  252,  446. 

Globulites,  416. 

Gmelinite,  301. 

Gneiss,  439. 

Gold,  109. 

Goslarite,  156. 

Gothite,  182. 

Grahamite,  326. 

Gramenite,  307. 

Grammatite,  249. 

Granite,  437, 

Granitone,  449,  450. 

Granular  quartz,  435. 

Granulyte,  439. 

Graphic  granite,  438,  439. 

tellurium,  118. 
Graphite,  107. 
Grastite,  319. 
Gray  antimony,  «.  Stibnite, 

copper,  135. 
Green  earth,  307. 

sand,  429. 
Greenockite,  159. 
Greenovite,  290. 
Greenstone,  446,  448. 
Greisen,  441. 
Grindstones,  427. 
Grit,  426. 
Grochauite,  319. 
Groppite,  314. 
Grossularite,  257. 
Grunauite,  166. 
Guadalcazarite,  129. 
Guanajuatite,  102. 
Guano,  213. 
Guarinite,  291. 
Gummite,  170. 


4-G4 


GENERAL   INDEX. 


Gurhofite,  219. 
Guyaquillite,  325. 
Gymnite,  309. 
Gypsum,  56,  210. 
Gyrolite,  293. 

Haidingerite,  214 
Hair-salt,  205. 
Halite,  224. 
Hallite,  318. 
Halloysite,  312. 
HalotricMte,  182,  198. 
Hamburg1  white,  221. 
Harmotome,  301. 
Harrisite,  133. 
Haitite,  324. 

Hatchettite,  Hatchettine,  324. 
Hatchettolite,  170,  214. 
Hauerite,  188. 
Haureaulite,  191. 
Hausmannite,  189. 
Hauyne,  Haiiynite,  270. 
Hauynophyre,  452. 
Haydenite,  301. 
Hayesine,  212. 
Heavy  spar,  220. 
Hebronite,  199. 
Hedenbergite,  246. 
Hedyphane,  152. 
Heliotrope,  237. 
Helminthe,  319. 
Helvite,  Kelvin,  256. 
Hematite,  176,  455. 

Brown,  181,  Red,  176. 
Hemi-dioryte,  443. 
Henwoodite,  200. 
Hercynite,  196.    . 
Herderite,  199. 
Herschelite,  301. 
Hessite,  118. 
Hetaerolite,  189. 
Heterosite,  191. 
Heulandite,  303. 
Hisingerite,  315. 
Hcernesite,  207. 
Homilite,  289. 
Honey-stone,  201. 
Hopeite,  158. 
Hornblende,  249,  251. 

schist,  446. 
Horn  quicksilver,  129. 

silver,  120. 
Hornstone,  237. 


Horse-flesh  ore,  v.  Bornite. 
Hortonolite,  256. 
Houghite,  194. 
Howlite,  212. 
Huascolite,  155. 
Hiibnerite,  183. 
Hudsonite,  246. 
Humboldtilite,  261. 
Humboldtite,  289. 
Humite,  281. 
Hureaulite,  191. 
Hyacinth,  259,  260,  284. 
Hyalite,  240. 
Hyalomelan,  452. 
Hyalophane,  276. 
Hyalosiderite,  255. 
Hyalotecite,  153. 
HydrargiJlite,  194. 
Hydraulic  limestone,  217,  431 
Hydroboracite,  212. 
Hydrocarbons,  320. 
Hydrocerussite,  153. 
Hydrochloric  acid,  231. 
Hydrocyanite,  138. 
Hydrodolomite,  220. 
Hydrogen,  231. 
Hydromagnesite,  204,  207. 
Hydro-mica  Group,  312. 
Hydromica  schist,  440. 
Hydrophane,  240. 
Hydrophite,  309. 
Hydrotalcite,  194. 
Hydrozincite,  157. 
Hypersthene,  244. 
Hypfrsthenyte,  450,  451. 
Hyperyte,  450. 

Iberite,  315. 

Ice,  crystallization  of,  4. 
Iceland  spar,  215. 
Idocrase,  261. 
Idrialine,  Idrialite,  324. 
Ihleite,  182. 
Ilmenite,  178. 
Ilvaite,  263. 
Inclusions,  423. 
Indianite,  275. 
Indicolite,  283. 
Infusorial  earth,  241. 
lodargyrite,  121. 
Iodide,  Mercury,  129. 

Silver,  121. 
lodyrite,  121. 


GENERAL   INDEX. 


465 


lolite,  264. 

Hydrous,  Slo". 
lonite,  325. 
Iridosmine,  127. 
Iron,  171. 
Iron,  Ores  of,  171,  455. 

Magnetic,  178,  455. 

pyrites,  172. 

sinter,  185. 

Ironstone,  Clay,  177,  181. 
Isenite,  448. 
Iserine,  u.  Menaccanite. 
Isoclasite,  139. 
Itabyrite,  440,  455 
Itacolumyte,  104,  436. 
Ittnerite,  270. 
Ixolyte,  324. 

Jade,  250. 
Jadeite,  263. 
Jamesonite,  149. 
Jargon,  260. 
Jarosite,  182. 
Jasper,  237. 

rock,  437 

Jaspery  clay  iron-stone,  177. 
Jefferisite,  317. 
Jeffersonite,  246. 
Jelletite,  258. 
Jenkinsite,  309. 
Jenzscliite,  241. 
Jet,  328. 
Johannite,  171. 
Jollyte,  316. 
Joseite,  102. 

Kalinite,  198. 
Kammererite,  318. 
Kaneite,  188. 

Kaolin,  Kaolinite,  280,  310. 
Karyinite,  152. 
Keiihauite,  203,  291, 
Kermesite,  101. 
Kerrite,  318. 

Kersanton,  Kersantyte,  444 
Kerstenite,  150. 
Kieserite,  205. 
Killinite,  248. 
Kinzigyte,  444. 
Kjerulftne,  207. 
Knebelite,  256. 
Kobellite,  149. 
Kochelite,  202. 


Kongsbergite,  117. 
Konigite,  Konigine,  138. 
Konlite,  324. 
Kottigite,  156, 167. 
Kotschubeite,  319. 
Kreittonite,  196. 
Krennerite,  116. 
Krisuvigite,  138. 
Kronkite,  138. 
Kupfferite,  252. 
Kyanite,  286. 

Labradioryte,  448. 
Labrador  feldspar,  27(5. 
Labradorite,  276. 
Labradorite-dioryte,  448. 
Lagonite,  182. 
Lampadite,  190. 
Lanarkite,  151. 
Langite,  138. 
Lanthanite,  203. 
Lanthanum  ores,  201. 
Lapis-lazuli,  270. 
Lapis  ollaris,  304. 
Larderellite,  231. 
Latrobite,  v.  Anorthite. 
Laumontite,  Laumonite,  293. 
Laurite,  127. 
Lazulite,  199. 
Lead,  ores  of,  145 
Leadhillite,  151. 
Lecontite,  231. 
Lederite,  291. 
Lehrbachite,  149. 
Lenzinite,  312. 
Leopoldite,  v.  Sylvite. 
Lepidokrokite,  182. 
Lepidolite,  268. 
Lepidomelane,  266. 
Leptinyte,  439. 
Lettsomite,  v.  Cyanotrichite. 
Leuchtenbergite,  319. 
Leucite,  271 
Leucitophyre,  452. 
Leucityte,  443. 
Leucophanite,  256. 
Leucopyrite,  176. 
Levyne,  Levynite,  301. 
Lherzolyte,  453. 
Libethenite,  139. 
Liebigite,  171. 
Lievrite,  <D.  Ilvaite. 
Lignite,  328. 


466 


GENERAL    INDEX. 


Lillite,  316. 
Limbacliite,  309. 
Limburgyte,  453. 
Lime-titanate,  v.  Perofskite. 
Limestone,  216,  430,  432. 
Limnite,  182. 
Limonite,  181. 
Linarite,  138. 
Lindackerite,  168. 
Linnaeite,  164. 
Liroconite,  139. 
Lithiophilite,  190. 
Litliium  phosphates,  190,  199. 
Lithographic  stone,   217. 
Lithomarge,  312. 
Liver  ore,  129. 
Livingstonite,  101. 
Lodestone,  141,  179. 
Loess,  4-29. 
Loganite,  318. 
Lollingite,  176. 
Lophoite,  319. 
Loweite,  227,  206. 
Lowigite,  199. 
Loxoclase,  278. 
Ludlamite,  185. 
Ludwigite,  206. 
Lumachelle,  431. 
Liineburgite,  207. 
Lydian  stone,  237. 
Lyncurium,  284. 

Made,  285. 

Maconite,  318. 

Magnesite,  207. 

Magnesium,  Compounds  of,  204. 

Magnetic  iron  ore,  178,  455. 

pyrites,  174. 
Magnetite,  59,  178,  423. 
Magnoferrite,  204. 
Magnolite,  129. 
Malachite,  Blue,  141. 

Green,  140,  200. 
Malacolite,  246. 
Malacon,  260. 
Maldonite,  110. 
Malinowskite,  136. 
Manganblende,  188. 
Manganepidot,  «.  Epidote. 
Manganese  ores,  188. 

spar,  247. 
Manganite,  189. 
Marble,  216,  431,  432. 


Marble,  Verd-antique,  454 
Marcasite,  174. 
Margarite,  319. 
Margarodite,  313. 
Margarophyllite  Section,  304. 
Marialite,  269. 
Marl,  432. 

Marmatite,  v.  Sphalerite. 
Marmolite,  308. 
Marsh  gas,  321. 
Martite,  177. 

Mascagnite,  Mascagnine,  231. 
Masonite,  320. 

Matlockite=Lead  oxichloride. 
Medjidite,  171. 
Meerschaum,  306. 
Meionite,  269. 
Melaconite,  137. 
Melanite,  258. 
Melanochroite,  151. 
Melanolite,  315. 
Melanophlogite,  241. 
Melanterite,  182. 
Melaphyre,  450. 
Melilite,  Mellilite,  261. 
Melinophane,  256. 
Meliphanite,  256. 
Mellite,  201. 
Menaccanite,  178. 
Mendipite,  149. 
Mendozite,  198. 
Meneghinite,  149. 
Menilite,  240. 
Mercury,  Ores  of,  128. 

Native,  128. 
Mesitine,  Mesitite,  186. 
Mesolite,  299. 
Mesotype  v.  Natrolite. 
Metabrushite,  214. 
Metachlorite,  319. 
Metacinnabarite,  129. 
Metadoleryte,  452. 
Metaxite,  308. 
Metaxoite,  317. 
Miargyrite,  120. 
Miarolyte,  438. 
Miascyte,  444. 
Mica,  265. 
Mica-argillyte,  441. 

dioryte,  444. 

phyllyte,  441. 

schist,  440. 
Michaelsonite,  263. 


GENEKAL   INDEX, 


467 


Microcline,  278. 
Microlite,  202,  214. 
Microlites,  416,  fig.  6. 
Microsommite,  270. 
Middletonite,  325. 
Milarite,  252. 
Millerite,  164. 
Millstone  grit,  426. 
Mimetene,  Mimetite,  46,  152. 
Mineral  coal,  327. 

oil,  321. 

pitch,  326. 
Minette,  441. 
Minium,  149. 
Mirabilite,  41,  226. 
Misenite,  227. 
Mispickel,  175. 
Mizzonite,  269. 
Mocha  stone,  236. 
Molybdate,  Lead,  151. 
Molybdenite,  96. 
Molybdite,  97. 
Monazite,  41,  203. 
Monimolite,  152. 
Monradite,  295. 
Montanite,  102. 
Monticellite,  256. 
Montmartite,  v.  Gypsum. 
Montmorillonite,  307. 
Montronite,  307. 
Moonstone,  277,  279. 
Mordenite,  304. 
Morenosite,  168. 
Mosandrite,  263. 
Moss  agate,  236. 
Mottramite,  139. 
Mountain  cork,  250. 

leather,  250. 

tallow,  324. 
Muller's  glass,  240. 
Mundic,  174. 
Muntz  metal,  144. 
Muriatic  acid,  231. 
Muromontite,  263. 
Muscovite,  267. 
Muscovy  glass,  268. 
Miisenite,  v.  Siegenite. 

Nadorite,  152. 
Nagyagite,  116,  149. 
Naphtha,  321. 
Naphthaline,  324. 
Natroborocalcite,  212. 


Natrolite,  299. 
Natron,  229, 
Naumannite,  118. 
Needle  ore,  v,  Aikinite. 
Neft-gil,  324. 
Nemalite,  204 
Neotocite,  316, 
Nepheline-doleryte,  452. 
Nephelinyte,  452, 
Nephelite,  Nepheline,  269. 
Nephrite,  250. 
Newjanskite,  127, 
Niccolite,  166. 

Nickel  glance,  n.  Gersdorffite. 
Nickel-gyomite,  309. 
Nickel,  Ores  of,  164. 

stibine,  166, 
Nigrine,  162. 
Niobite,  V,  Columbite. 
Niobium,  Compounds  of,  184. 
Nitrate,  Calcium,  214. 

Potassium,  22a 

Sodium,  229. 
Nitratine,  229. 
Nitre,  228. 
Nitrocalcite,  214. 
Nitromagnesite,  206. 
Nohlite,  202. 
Noryte,  450. 
Nosean,  Nosite,  270. 
Noumeite,  168. 
Novaculyte,  436,  453. 
Nuttalite,  269. 

Ochre,  Red,  167,  176, 

Yellow,  181. 
Octahedrite,  163. 
CEllacherite,  314. 
CErstedite,  260, 
Ogcoite,  319. 
Okenite,  293. 
Oligoclase,  44,  276. 
Olivenite,  139. 
Olivine,  255. 
Onyx,  236. 
Oolite,  216. 
Opal,  239. 
Opal,  Jasper,  240. 
Ophiolite,  308. 
Ophiolyte,  454. 
Ophite,  447. 
Orangite,  296. 
Orpiment,  99. 


468 


GENERAL   INDEX. 


Orthite,  263. 
Orthoclase,  44,  278. 
Osteolite,  213. 
Ottrelite,  320. 
Ouvarovite,  258. 
Oxide,  Cobalt,  167. 

Iron,  176. 

Lead,  149. 

Magnesium,  204. 

Manganese,  188. 

Tin,  160. 

Uranium,  169. 

Zinc,  155. 
Ozarkite,  298. 
Ozocerite,  Ozokerite,  324 

Pachnolite,  197. 
Pacos,  121. 
Pagodite,  312. 
Palagonite,  312. 
Palladium,  127. 
Paraffin,  324. 
Paragonite,  314. 

schist,  441. 
Paranthine,  269. 
Parasite,  v.  Boracite. 
Pargasite,  251. 
Parisite,  203. 
Parophite,  314. 
Parophite  schist,  441. 
Pattersonite,  319. 
Pealite,  v.  Geyserite. 
Pearl  sinter,  437. 

spar,  219. 

stone,  443. 
Pectolite,  293. 
Peganite,  200. 
Pegmatolite,  v.  Orthoclase. 
Pegmatyte,  438,  439. 
Pelagite,  189. 
Pelhamite,  318. 
Pencil-stone,  306. 
Pennine,  Penninite,  318. 
Pennite,  220. 
Peperino,  429. 
Periclase,  Periclasite,  204. 
Peridot,  v.  Chrysolite. 
Peridotyte,  451. 
Perofskite,  Perowskit,  163. 
Petalite,  248. 
Petroleum,  321. 
Petrosilex,  442. 
Petzite,  116,  118. 


Phacolite,  301. 

Pharmacolite,  214. 

Pharmacosiderite,  185', 

Phenacite,  254. 

Phillipite,  138. 

Phillipsite,  302. 

Phlogopite,  68,  266. 

Phcenicochroite,  151. 

Pholerite,  312. 

Phonolyte,  444. 

Phosgenite,  153. 

Phosphate,  Aluminum,  199,  200. 

Ammonium,  231. 

Calcium,  212,  214. 

Cerium,  203. 

Copper,  139. 

Iron,  184,  185, 191. 

Lead,  151. 

Manganese,  190,  191. 

Uranium,  170. 

Yttrium,  203. 
Phosphochalcite,  139. 
Phosphorite,213. 
Phrenite,  295. 
Phyllite,  320. 
Phyllyte,  428. 
Physalite,  287. 
Pickeringite,  198. 
Picotite,  195. 
Picrolite,  308. 
Picromerite,  205,  227. 
Picrophyll,  295. 
Picrosmine,  295. 
Picryte,  453. 
Piedmontite,  262. 
Pilinite,  304. 
Pimelite,  168. 
Pinguite,  307. 
Finite,  312. 
Pinitoid,  312. 
Pipe- clay,  427. 
Pipestone,  429. 
Pisanite,  182. 
Pisolite,  216. 
Pistacite,  262. 
Pitchblende,  169. 
Pitkarandite,  295. 
Pitticite,  v.  Iron  Sinter. 
Plagloclase,  275,  425. 
Plagionite,  149. 
Plasma,  237. 
Plaster  of  Paris,  211. 
Platinum,  Native,  124. 


GENERAL   INDEX. 


469 


Platiniridium,  127. 
Pleonaste,  v.  Spinel. 
Plumbago,  107. 
Plumbic  oclire,  149. 
Plumbogummite,  149. 
Plumose  mica,  267. 
Polianite,  v.  Pyrolusite. 
Polishing  powder,  430. 
Pollucite,  Pollux,  254. 
Polyargite,  312. 
Polyargyrite,  120. 
Polybasite,  120,  136. 
Polycrase,  202. 
Polyhalite,  205,  227. 
Polylite,  246. 
Polymignite,  202,  260. 
Porcelain  jasper,  442. 
Porcelanyte,  442. 
Porcellophite,  308. 
Porfido  verde  antico,  452. 
Porpezite,  127. 
Porphyrite,  447. 
Porphyritic  structure,  415. 
Porphyry,  417,  442,  448. 

Antique  green,  452. 

Antique  red,  415,  447. 
Porphyryte,  447. 
Portor,  431. 

Potassium,  Compounds  of,  223. 
Potstone,  304. 
Potter's  clay,  429. 
Pozzuolana,  428. 
Prase,  235. 
Pregattite,  314. 
Prehnite,  295. 
Priceite,  212. 
Prochlorite,  54,  319. 
Propylyte,  447. 
Protogine,  440. 
Protovermiculite,  318. 
Proustite,  119,  121. 
Przibramite,  159. 
Psammite,  v.  Sandstone. 
Pseudomalachite,  139. 
Pseudophite,  318. 
Pseudotriplite,  191. 
Psilomelane,  189. 
Psittacinite,  139. 
Pudding-stone,  426. 
Purple  copper,  v.  Bornite. 
Pycnite,  287. 
Pyrallolite,  295. 
Pyrargillite,  315. 


Pyrargyrite,  119, 121. 
Pyreneite,  258. 
Pyrite,  5,  6,  172. 
Pyrites,  Arsenical,  175. 

Auriferous,  173. 

Capillary,  164. 

Cobalt,  164. 

Cockscomb,  174. 

Copper,  133. 

Hepatic,  174. 

Iron,  172. 

Magnetic,  174. 

Radiated,  174. 

Spear,  174. 

Variegated,  134. 

White  iron,  174. 
Pyrochlore,  202,  214. 
Pyrochroite,  189. 
Pyrolusite,  188. 
Pyromorphite,  151. 
Pyrope,  258. 
Pyrophosphorite,  214. 
Pyrophyllite,  306. 

slate,  455. 
Pyrophyllyte,  455. 
Pyrophysalite,  287. 
Pyrosclerite,  317. 
Pyrosmalite,  296. 
Pyrostilpnite,  120. 
Pyroxene,  245. 
Pyroxenyte,  452. 
Pyrrhopcecilon,  445. 
Pyrrhosiderite,  182. 
Pyrrhotite,  174. 

Quartz,  53,  54,  58,  233,  238,  435. 

andesyte,  447. 

dioryte,  446. 

felsyte,  443. 

propylyte,  447. 

syenyte,  445. 

trachyte,  442. 
Quartzyte,  435. 
Quick  lime,  217. 
Quicksilver.     See  Mercury. 

Raimondite,  182. 

Realgar,  99. 

Red  antimony,  101. 

chalk,  177. 

copper  ore,  136. 

hematite,  176. 

lead,  149. 


470 


GENERAL   INDEX. 


Red  ochre,  167,  176. 

silver  ore,  119. 

zinc  ore,  155. 
Reddingite,  191. 
Redruthite,  132. 
Refdanskite,  308. 
Remingtonite,  168. 
Rensselaerite,  305,  454. 
Retinalite,  308. 
Rhabdophane,  203. 
Rh«tizite,  286. 
Rhodium  gold,  110. 
Rhodizite,  206. 
Rhodoehrome,  318. 
Rhodochrosite,  191. 
Rhodonite,  191,  247. 
Rhodophyllite,  318. 
Rhomb-spar,  219. 
Rhyolyte,  418,  fig.  8. 
Ripidolite,  3,18. 

Rittingerite,  near  Freieslebenite. 
Rivotite,  139. 
Rock  cork,  v.  Hornblende. 

crystal,  234. 

meal,  216. 

milk,  216. 

salt,  224. 
Rcepperite,  256. 
Ro3sslerite,  207. 
Rogersite,  203. 
Romeine,  Romeite,  214. 
Roscoelite,  314. 
Roselite,  168. 
Rosite,  312. 
Rosso  antico,  415,  447. 
Rothoffite,  258. 
Rottisite,  168,  310. 
Rubellite,  283. 
Ruby,  Spinel,  193. 
Ruby -blende,  v.  Pyrargyrite,  119. 
Ruby  silver,  119. 
Ruin  marble,  431. 
Ruthenium,  Ores  of,  127. 
Rutherfordite,  203. 
Rutile,  57,  162. 

Safflorite,  165. 

Sahlite,  246. 

Sal  ammoniac,  230. 

Salmiak,  230. 

Salt,  Common,  29,  224. 

Samarskite,  170,  202. 

Sandstone,  426. 


Sanidin,  278. 
Saponite,  310. 
Sapphire,  193. 
Sarcolite,  269. 
Sard,  236. 
Sardonyx,  236. 
Sartorite,  149. 
Sassolitc,  Sassolin,  97. 
Satin-spar,  210,  215. 
Saussurite,  263,  410,  449, 
Saussurite  group,  410. 
Savite,  v.  Natrolite. 
Scapolite,  268. 
Scarbroite,  296. 
Sceleretinite.  325 
Scheelite,  212. 
Schiller-spar,  309. 
Schorl  (pron.  Shorl),  283. 
Schorlomite,  292. 
Schreibersite,  175. 
Schrotterite,  296. 
Scolecite,  Scolezite,  299. 
Scorodite,  185. 
Scotiolite,  315. 
Selenate,  Copper,  135. 

Lead,  150. 
Selenide,  Lead,  149. 

Mercury,  149. 

Silver,  118. 
Selenite,  210. 
Selenpalladite,  127. 
Semiopal,  240. 
Senarmontite,  101. 
Sepiolite,  306. 
Sericite,  314. 

slate,  441. 

Serpentine,  307,  454 
Severite,  312. 
Seybertite,  320. 
Shale,  427. 
Siderite,  185. 
Siegenite,  164. 
Silaonite,  102. 
Silex,  v.  Quartz. 
Silica,  233. 
Silicate,  Copper,  141,  142. 

Lead,  153. 

Nickel,  168. 

Zinc,  157. 
Silicates,  242. 
Siliceous  sinter,  240,  437. 

slate,  436. 
Silicined  wood,  238. 


GENERAL   INDEX. 


471 


Silicoborocalcite,  212. 
Sillimanite,  285. 
Silt,  429. 
Silver,  116,  121. 

Compounds  of,  216. 

glance,  117. 
Sinter,  Siliceous,  240. 
Sipylite,  202. 
Sisserskite,  127. 
Skutterudite,  166. 
Smaltite,  Smaltine,  165. 
Smectite,  307,  312. 
Smithsonite,  156. 
Snow,  crystals  of,  4. 
Soapstone,  ^04,  454. 
Soda  nitre,  229. 
Sodalite,  270. 

Sodium,  Compounds  of,  223. 
Sommite,  269. 
Spaniolite,  136. 
Spathic  iron,  185. 
Spear  pyrites,  174. 
Speckstein,  v.  Steatite. 
Specular  iron,  176,  455. 
Speculum  metal.  144. 
Spelter,  158. 

solder,  144. 
Spessartite,  258. 
Sphserosiderite,  186. 
Sphalerite,  154. 
Sphene,  290. 
Spherocobaltite,  168. 
Spilite,  451. 
Spinel,  194,  204. 
Spinthere,  v.  Titanite. 
Spodumene,  248. 
Stalactite,  216. 
Stalagmite,  216,  432. 
Stannite,  159. 
Staurolite,  Staurotide,  291. 
Steatite,  304. 
Steatyte,  454. 
Stephanite,  119,  121. 
Stercorite,  231. 
Sterlingite,  0.  Damourite. 
Sternbergite,  118. 
Stibnite,  100. 
Stilbite,  302. 
Stilpnomelane,  307. 
Stinkstone,  217. 
Stolpenite,  307. 
Stolzite,  151. 
Strakonitzite,  295. 


Stratopeite,  316. 

Strengite,  185. 

Strigovite,  316. 

Stromeyerite,  118. 

Strontianite,  223. 

Strontium,  Compounds  of,  220. 

Struvite,  231. 

Stubelite,  316. 

Stylotypite,  136,  149. 

Succinum,  325. 

Sulphate,  Aluminum,  197,  198. 

Ammonium,  231. 

Barium,  220. 

Calcium,  210,  211. 

Cobalt,  168. 

Copper,  137,  138. 

Iron,  182. 

Lead,  150. 

Magnesium,  205. 

Nickel,  168. 

Potassium,  227. 

Sodium,  226,  227. 

Strontium,  222. 

Uranium,  171. 

Zinc,  156. 
Sulphide,  Antimony,  100. 

Arsenic,  99. 

Bismuth,  102.  v. 

Cadmium,  159. 

Cobalt,  164. 

Copper,  132,  133,  134.     - 

Iron,  172,  174. 

Lead,  145,  149. 

Manganese,  188. 

Mercury,  128,  130. 

Molybdenum,  96. 

Nickel,  164. 

Ruthenium,  127. 

Silver,  117,  118. 

Tin,  159. 

Zinc,  154,  155. 
Sulphur,  Native,  37,  94. 
Sulphuret,  see  Sulphide. 
Sulphuric  acid,  96. 
Sulphurous  acid,  96. 
Sunstone,  277,  279. 
Susannite  —  Rhoinbohedral  Lead* 

hillite. 

Sussexite,  206. 
Syenites,  445. 
Syenyte,  445. 

gneiss,  446. 
Sylvanite,  116,  118. 


473 


GENERAL   INDEX. 


Sylvine,  Sylvite,  224. 

Syngenite,  227. 
Szaibelyte,  206. 

Tabasheer,  241. 
Tabular  spar,  244. 
Tachhydrite,  205. 
Tachyaphaltite,  260. 
Tachylyte,  452. 
Tagilite,  139. 
Talc,  304. 
Talcose  schist,  454. 

slate,  441. 

Tantalates,  170,  184,  202,  214 
Tantalite,  184. 
Tapalpite,  118. 
Tasmanite,  326. 
Tellurate,  Bismuth,  102. 

Mercury,  129. 
Telluride,  Bismuth,  102. 

Gold,  115,  116,  118. 

Lead,  149. 

Mercury,  129. 

Silver,  118. 
Tellurite,  96. 
Tellurium,  Bismuthic,  102. 

Foliated,  ro.  Nagyagite. 

GrJ'Mc,  118. 

Native,  9(3. 
Tellurous  acid,  96. 
Tengerite,  203. 
Tennantite,  135. 
Tenorite,  137. 
Tephrpite,  256. 
Terenite,  312. 
Teschemacherite,  231. 
Teschenite,  448. 
Tetradymite,  102. 
Tetrahedrite,  121,  135. 
Thenardite,  227. 
Thermonatrite,  230. 
Thomsenolite,  197. 
Thomsonite,  298. 
Thorite,  296. 
Thraulite,  316. 
Thulite,  263. 
Tlmmite,  264. 
Thuringite,  319. 
Tiemannite,  129. 
Tile  ore,  137,  160. 
Till,  429. 
Tin,  Native,  159. 
Tin  ore,  Tin  stone,  160. 


Tin  pyrites,  159. 
Tinkal,  227. 
Titanic  iron,  178,  456. 
Titanite,  290. 
Titanium,  Ores  of,  162. 
Tiza,  v.  Ulexite. 
Tocornalite,  121. 
Tonalyte,  447. 
Topaz,  286. 

False,  235. 

Oriental,  193. 
Topazolite,  258. 
Torbanite,  325,  329. 
Torbernite,  170,  139. 
Touchstone,  237. 
Tourmaline,  282. 
Trachydoleryte,  447. 
Trachyte,  442. 
Tractolyte,  450. 
Trap,  451. 
Traversellite,  295. 
Travertine,  432. 
Tremolite,  249. 
Trichites,  416. 
Triclasite,  315. 
Tridymite,  88,  241. 
Tripestone,  212. 

Triphylite,  Triphyline,  184,  190. 
Triplite,  191. 
Triploidite,  191. 
Tripolite,  241. 
Tsipolyte,  430. 
Tritomite,  296. 
Tro'gerite,  171. 
Troilite,  175. 
Trona,  230. 
Troostite,  157. 
Tscheffkinite,  203,  291. 
Tschermakite,  v.  Oligoclase. 
Tschermigite,  198,  231. 
Tufa,  Tuffe,  428. 
Tufa,  Calcareous,  216. 
Tungstate,  Copper,  138. 

Iron,  183. 

Lead,  151. 

Lime,  212. 
Tungstic  ochre,  97. 
Tungstite,  97. 
Turgite,  182. 
Turquois,  200. 
Tyrolite,  139. 

Ulexite,  212. 


GENERAL   INDEX. 


473 


Ullmannite,  166. 
Ultramarine,  270. 
Unakyte,  440. 
Unghwarite,  307. 
Unionite,  v.  Zoisite. 
Uraconise,  Uraconite,  171. 
Uralite,  247. 
Uranin,  Uraninite,  169. 
Uranite,  170. 
Uranium,  Ores  of,  169. 
Uranmica,  170. 
Uranoclialcite,  171. 
Uranocircite,  171. 
Uranospinite,  170. 
Uranotantalite,  170. 
Uranvitriol,  171. 
Urpethite,  334. 


Valentinite,  101. 
Vanadate,  Copper,  139. 

Lead,  152. 
Vanadinite,  152. 
Variolyte,  449. 
Variscite,  200. 
Vauquelinite,  151. 
Velvet  copper  ore,  138. 
Venerite,  319. 
Venice  white,  221. 
Verd-antique,  308,  454. 

Oriental,  415. 

Verde  di  Corsica  duro,  449, 
Vermiculite,  317. 
Vermilion,  129. 
Vesuvianite,  261. 
Veszelyte,  139. 
Villarsite,  296. 
Viridite,  317. 
Vitreous  copper,  133. 

silver,  117. 
Vitriol,  Blue,  137. 

Green,  182. 

Iron,  182. 

White,  156. 
Vivianite,  184. 
Voglianite,  171. 
Voglite,  171. 
Volborthite,  139. 
Volknerite,  194. 
Voltaite,  182. 
Voltzite,  155. 
Vorhauserite,  308. 
Vulpinite,  212. 


Wacke,  428. 
Wad,  190. 
Wagnerite,  206. 
Walchowite,  325. 
Walpurgite,  171. 
Warringtonite,  «.  Brochantite. 
Warwickite,  206. 
Washingtonite,  178. 
Water,  4,  231. 
Wavellite,  201. 
Websterite,  199. 
Wehrlite,  102. 
Wernerite,  268. 
Westanite,  v.  Fibrolite. 
Wheel-ore,  136. 
Whetstone,  436,  453. 
White  vitriol,  156. 

arsenic,  99. 
Whitneyite,  135. 
Wichtine,  Wichtisite,  252. 
Willcoxite,  320. 
Willemite,  157,  256. 
Williamsite,  308. 
Wilsonite,  312. 
Winkworthite,  v.  Howlite. 
Witherite,  221. 
Wittichenite  =  Cu3BiS3. 
Wittingite,  316. 
Wohlerite,  256,  260. 
Wolfram,  Wolframite,  183. 
Wollastonite,  244. 
Wollongongite,  326. 
Wood-opal,  240. 
Wood  tin,  160. 

Woodwardite,  near  Cyantrochite. 
Wulfenite,  151. 
Wurtzite,  155. 

Xanthophyllite,  320. 
Xanthosiderite,  182. 
Xenotime,  203. 
Xylotine,  295. 

Yenite,  263. 
Youngite,  155. 
Ytter-garnet,  258. 
Yttrium  ores,  201. 
Yttrocerite,  201. 
Yttroilmenite,  170. 
Yttrotantalite,  202, 

Zaffre,  168. 


474 


GENERAL   INDEX. 


Zaratite,  168. 
Zeagonite,  296. 
Zeolite  Section,  297. 
Zepharovichite,  201. 
Zeunerite,  170. 
Zietiisikite,  324. 
Zinc,  ores  of,  154. 

blende,  154. 

bloom,  v.  Hydrozincite. 
Zinc  ore,  red,  155. 
Zmcite,  155. 


Zinkenite,  149. 
Zinnwaldite,  268. 
Zippeite,  171. 
Zircon,  259. 
Zirconite,  260. 
Zircon-syenyte,  446. 
Zoblitzite,  809. 
Zoisite,  263. 
Zonochlorite,  296. 
Zorgite,  149. 
Zwieselite,  v.  Triplite. 


MINERALOGY-METALLURGY-ASSAYING,  ftc,,  ftc. 


JOHN  WILEY  &  SONS,  15  Astor  Place,  New  York, 

PUBLISH 

I. 

A  SYSTEM  OF1  MINERALOGY— DESCRIPTIVE  MINERALOGY, 

comprising  the  most  recent  discoveries.  By  James  Dwight  Dana,  Prof, 
of  Geology  and  Mineralogy,  Yale  College,  aided  by  Prof.  George  Jarvis 
Brush,  of  Sheffield  Scientific  School.  Fifth  edition,  re-written  and  en- 
larged. Illustrated  with  upwards  of  600  wood-cuts.  Thick  8vo, 

cloth,  including  three  Appendixes  complete  to  1882 $10.00 

This  work  contains  full  descriptions,  physical,  chemical  and  geographical,  of 
all  known  minerals  up  to  the  time  of  publication.  Besides  giving  the  composition 
of  minerals  at  length,  it  includes  all  the  analyses  that  had  been  made  from  the  first 
beginning  of  analytical  chemistry,  along  with  references  to  their  authors,  and  the 
works  or  memoirs  in  which  they  appeared.  It  also  gives,  under  each  species,  de- 
tailed statements  of  the  blowpipe  characters  of  each,  prepared  by  Prof.  Brush, 
extended  notices  of  Foreign,  as  well  as  American  localities— the  latter  with  special 
f  ullness  as  regards  modes  of  occurence  and  associated  minerals,— and  a  complete 
historical  account  of  the  names  of  minerals  and  their  varieties,  and  of  all  syno- 
nyms. 

The  volume,  as  now  Issued,  includes  three  appendixes :  the  first,  prepared 
"by  Prof.  G  J.  Brush,  and  the  second  and  third  by  &r.  E.  S.  Dana,  bringing  the 
subject  down,  as  regards  new  species,  and  new  determinations  of  the  old,  to  the 
date  of  publication,  in  1883. 

II. 

MANUAL  OF   DETERMINATIVE   MINERALOGY,  with  an  intro- 
duction on  BLOWPIPE  ANALYSIS.      By  George  J.  Brush,  Professor  of 
Mineralogy  in  the  Sheffield  Scientific  School  of  Yale  College.     Third 
edition,  revised  and  corrected,  with  NEW  NOTATION.     8vo,  cloth,  $3.50 
The  method  of  instruction  adopted  in  this  work  is  first  to  give  the  student  a 
preliminary  knowledge  of  the  use  of  the  blowpipe  and  other  apparatus  employed 
in  the  determination  of  minerals.     It  includes  a  systematic  course  of  Qualitative 
Blowpipe  Analysis,  with  tables  of  reactions  of  the  metals,  metallic  oxides,  and 
earths  with  and  without  fluxes,  concluding  with  an  alphabetical  list  of  elements 
and  compounds,  with  their  characteristic  blowpipe  and  other  reactions.    This  is 
followed  by  tables  for  the  determination  of  mineral  species,  which  are  so  arranged 
that  by  means  of  a  few  simple  experiments  before  the  blowpipe  and  in  the  wet 
way,  the  mineral  is  quickly  limited  to  a  group  of  a  few  species ;  among  the  mem- 
bers of  this  group  the  mineral  is  distinguished  by  other  trials,  and  when  from  these 
various  experiments  the  mineral  species  is  finally  decided  upon,  the  conclusion  is 
confirmed  or  corrected  by  reference  to  the  chemical  composition,  crystalline  form 
and  other  physical  characteristics  given  in  the  tables. 

An  acquaintance  with  the  use  of  the  blowpipe,  such  as  is  gained  by  the  study  of 
the  introductory  pages,  and  with  the  manner  of  performing  the  simplest  opera- 
tions of  solution  and  precipitation,  is  all  that  is  necessary  in  making  the  requisite 
trials. 

These  determinative  tables,  while  founded  upon  the  tenth  edition  of  Professor 
Von  Kobell's  well-known  work,  are  arranged  in  an  entirely  new  form,  much  more 
convenient  for  use,  and  contain,  besides,  a  large  amount  of  additional  matter  in 
regard  to  old,  as  well  as  new,  mineral  species. 
The  Same  work— Second  Edition— OLD  NOTATION.    8vo,  cloth $2.50 


III. 

A  TEXT-BOOK  OF  MINERALOGY.  With  an  extended  treatise  on 
CRYSTALLOGRAPHY  and  PHYSICAL  MINERALOGY.  By  Edward  S.  Dana, 
Curator  of  Mineralogy,  Yale  College,  on  the  plan  and  with  the  co-opera- 
tion of  Prof.  James  D.  Dana.  Illustrated  with  upwards  of  800  wood- 
cuts and  one  colored  plate.  New  revised  edition,  1883.  8vo,  cloth.  $3.50 

This  work  is  especially  designed  for  those  who  desire  to  make  themselves 
acquainted  with  the  principles  and  methods  of  Crystallography,  and  of  the  no  less 
important  branch  of  Optical  Mineralogy.  With  this  end  in  view,  about  one-haif 
of  the  whole  work,  which  covers  nearly  500  pages,  is  devoted  to  these  subjects,  and 
the  remainder  is  given  to  the  description  of  mineral  species. 

The  system  of  Crystallography  adopted  is  that  of  Naumann,  which  has  the 
great  advantage  of  being  most  readily  intelligible  to  the  beginner.  The  six  crys- 
talline systems  are  taken  up  in  succession,  and  the  forms  occurring  under  each, 
with  their  symbols,  are  described,  and  numerous  figures  are  added  as  illustrations 
of  the  text.  The  methods  of  Mathematical  Crystallography  are  then  explained, 
and  the  application  of  them  to  all  the  ordinarily  occurring  cases  given  in  full,  so 
that  any  one  with  a  knowledge  of  ordinary  trigonometry  can  soon  learn  to  make 
all  necessary  calculations.  This  subject  closes  with  a  chapter  on  the  measurements 
of  crystals,  and  others  on  twin  crystals,  the  irregularities  of  crystals,  crystalline 
aggregates,  and  pseudomorphous  crystals. 

Supplementary  to  this  portion  of  the  work,  there  is  given  in  the  Appendix,  a 
chapter  upon  Miller's  System  of  Crystallography,  in  which  its  principles  and 
methods  are  clearly  and  concisely  stated,  and  another  upon  the  methods  of  draw- 
ing crystals. 

In  the  description  of  the  physical  characters  of  minerals,  their  distinguishing 
optical  properties  are  developed  with  especial  fullness,  preceded  by  a  statement  of 
the  fundamental  principles  of  Optics  upon  which  they  depend,  and  a  description 
of  the  instruments  used  in  the  research.  A  colored  plate  in  the  beginning  of  the 
volume  shows  the  interference-figures  observed  when  sections  of  different  biaxial 
crystals  are  viewed  in  polarized  light. 

The  section  on  Chemical  Mineralogy  also  includes  a  brief  description  of  the 
methods  of  blowpipe  analysis,  and  a  table  for  the  determination  of  minerals  based 
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IV. 

MANUAL  OP  MINERALOGY  AND  LITHOLOGY.  Containing  ele. 
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Mineralogist  and  Geologist,  and  for  instruction  in  Schools  and  Colleges. 
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The  work  contains  an  account  of  the  elements  of  Crystallography,  and  of  the 
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